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Healthcare Provider Q&A

This Q&A document includes general information about COVID-19 vaccines and questions and answers specific to the vaccines currently in use in BC.
COVID-19 vaccine information is evolving, and as such, this Q&A will be updated as new information and new COVID-19 vaccines become available in BC.

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COVID-19 disease

Information on COVID-19 epidemiology is continually evolving. For the most up-to-date data on COVID-19 cases, go to:
 
While preventive measures such as physical distancing, frequent handwashing, and wearing a mask help to reduce the risk of exposure and transmission of SARS-CoV-2, the virus that causes COVID-19 infection and disease, these measures alone are not enough. The combination of COVID-19 vaccination and following BCCDC’s prevention measures offer the best protection from COVID-19.  Ending this pandemic requires all the tools we have available, including, most importantly, vaccination. 

COVID-19 vaccination protects not only the person being vaccinated, but also people around them, including those who are unable to get the vaccine. The more people in a community who are immunized and protected from COVID-19, the harder it is for COVID-19 to spread.
 
 
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Vaccine development and safety 

Factors that allowed COVID-19 vaccines to progress quickly include advances in vaccine development technology, government funding and purchase commitments, international collaboration among health professionals, researchers, industry and governments to develop the vaccines, rapid recruitment of participants for clinical trials, and streamlined vaccine approval processes by the regulatory body at Health Canada. Canada’s rigorous vaccine approval process has remained in place to assess COVID-19 vaccines. 

As for all vaccines and treatments that are authorized in Canada, Health Canada reviews the evidence and scientific data and decides whether to authorize the COVID-19 vaccine and will only do so when the evidence shows that the vaccine:
  • is safe, effective and of good quality and
  • demonstrates that the benefits outweigh the known and potential risks
Health Canada’s approval of the Pfizer-BioNTech vaccine on December 9, 2020 is an example of this accelerated process. Health Canada ensured that the Pfizer-BioNTech vaccine, laboratory studies and three phases of double-blind randomized clinical trials have shown safety, immunogenicity (ability to generate an immune response) and efficacy (ability to prevent COVID-19 disease) of this vaccine in animals and in adolescents and adults 16 years of age and older. Approximately 44,000 individuals randomized (1:1) to receive either the vaccine or placebo participated in phases 2 and 3 of the clinical trials.1  This population has been considered sufficient to approve vaccine based on safety and efficacy.

Health Canada also has processes in place to share information with other countries’ regulatory bodies including the US Food and Drug Administration and the European Medicines Agency. 

Once a vaccine is approved, vaccine safety and effectiveness are continuously monitored to detect rare serious or unexpected side effects.
 
The Biologic and Radiopharmaceutical Drugs Directorate (BRDD), which is part of Health Canada, supervises all aspects of vaccine production and quality control throughout the vaccine’s lifecycle. When a manufacturer develops enough scientific and clinical evidence of a vaccine’s safety, efficacy, and quality, they file a complete package of information that is submitted to BRDD for market authorization. A submission contains data from scientific studies, including laboratory and clinical studies, and information about the manufacturing process, including the manufacturing facility and manufacturing method. BRDD thoroughly reviews the submission to determine whether the benefits of a vaccine outweigh any potential risks. BRDD also reviews procedures for the manufacturer’s safety monitoring and any plans to minimize any identified risks. In addition, BRDD may visit the manufacturing site to evaluate the manufacturing process’ quality and make sure the manufacturer can carry out the necessary quality controls for the vaccine. 

The expedited review performed for COVID-19 vaccines has been possible because of a number of administrative changes to the process. These have included allowance of submission of data when available rather than the sponsor needing to wait until the entire data package is complete prior to submission. As well, for approval of these vaccines in Canada and many countries, there has been allowance for a shorter period of follow-up of people enrolled into the phase 3 clinical trials, whereas for non-pandemic vaccines, that follow-up period is typically upwards of one year. As a result, the clinical trials will continue to accrue cases and safety information for up to two years following immunization. Results from these studies will be reported in the future and will provide additional information about issues such as duration of protection from the vaccine(s).

 
For an effective conversation about COVID-19 vaccines, we can start from a place of compassion and understanding. Patients consistently rank healthcare providers as their most trusted source for vaccine information. Be transparent about the latest vaccine(s) information, reassure that we have a robust vaccine safety system in Canada, and emphasize vaccines’ role to protect recipients and the people around them. Your willingness to listen to the patients’ concerns will play a significant role in building trust in you and your recommendation. If a patient has concerns or questions, this doesn’t necessarily mean they won’t accept a COVID-19 vaccine. Sometimes patients simply want your answers to their questions. Once you’ve answered their questions, let them know that you are open to continuing the conversation. Encourage your patients to schedule another appointment or go to the BCCDC or ImmunizeBC websites for more information about COVID-19 vaccination. Continue the conversation about COVID-19 vaccination during future visits.

‎Canada has a system of local, provincial, and national surveillance to carefully monitor adverse events following immunization and detect any vaccine safety concerns. Once a vaccine is approved, its safety is continuously being monitored as long as it is used. In most provinces and territories, including BC, health care providers are legally obliged to report all serious and unexpected adverse events following immunization to the medical health officer. Every serious or concerning event is reported to the BC Centre for Disease Control (BCCDC). These reports are reviewed at BCCDC and also sent to the Public Health Agency of Canada system called the Canadian Adverse Events Following Immunization System (CAEFISS), as are reports from all provinces and territories. Additional monitoring for adverse events is being done through a system called CANVAS (Canadian National Vaccine Safety Network) through which recipients of the vaccine can enroll to self-report adverse events following receipt of the vaccine, with serious events being reported on to the regional health authority.


Vaccine safety is also monitored at the international level. The World Health Organization’s International Drug Monitoring Program collects reports from over 75 countries and uses these global data to monitor for any vaccine safety concerns. In addition, all vaccine manufacturers must report serious adverse events of which they become aware, in Canada or internationally, to Health Canada. For COVID-19 vaccines, manufacturers are expected to implement enhanced monitoring activities.

More information about the Canadian vaccine safety surveillance system is contained in the Canadian Immunization Guide, Part 2 – Vaccine Safety, Vaccine safety and pharmacovigilance
 

‎Vaccine providers should refer to the BC Immunization Manual, Part 5 – Adverse Events Following Immunization for criteria on reporting adverse events following immunization (AEFI), and report AEFIs to the regional health authority. Information on reporting can be found on the BCCDC’s Surveillance Forms page under Adverse Events Following Immunization.


For more information and details on how to report an AEFI in BC go to the BCCDC Reporting Adverse Events Following Immunization: For BC Community Vaccine Providers.

1. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. Appendix A. 2021 Jan 12 [cited 2021 Jan 13]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines.html



 

COVID-19 vaccines in Canada

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General questions

‎Yes, individuals should continue to practice recommended public health measures for the prevention and control of SARS-CoV-2 infection and transmission regardless of vaccination with COVID-19 vaccine. At this time, there is insufficient evidence on the duration of protection of COVID-19 vaccines in preventing infection and reducing transmission of SARS-CoV-2 to recommend discontinuation of public health measures.  It is expected, however, that over time with more information about the impact of vaccination on COVID-19 transmission that there will be changes to the current prevention and control measures. 

 

‎Vaccine efficacy is calculated using data from vaccine clinical trials. The median period of follow up of vaccine and placebo recipients from phase 3 clinical trials was 2 months. Additional information about the duration of protection will continue to accrue in the clinical trials which will gather data for at least two years. Vaccine effectiveness is calculated using real-world experience and data once a vaccine has been in use in diverse populations and settings. Vaccine effectiveness information continues to be obtained from post-marketing surveillance evaluations including studies using the test-negative design in populations being targeted for early vaccination such as health care workers, and eventually through the long-standing Sentinel Physician Surveillance Network (SPSN) in Canada, which uses the test-negative study design to assess seasonal influenza vaccine effectiveness and has been running in four provinces contributing data, led by BCCDC.


Protection conferred by SARS-CoV-2 infection alone varies due to factors such as the degree of illness severity, age, and whether other comorbidities are present. Prior to the prevalence of the Omicron variant, protection due to vaccination was shown to be more durable than immunity from infection. In B.C., research demonstrated that prior to Omicron,  two doses of COVID-19 vaccine provides strong protection against infection and hospitalizations and that this protection was maintained for at least four months. Vaccine effectiveness against severe outcomes due to Omicron remains high, however the longevity of protection against Omicron is still unknown and will continue to be monitored. In addition, variant-specific vaccines are in development andd may be available in the coming months. 


Real world evidence suggests moderate to high vaccine effectiveness at preventing severe illness, such as hospitalization and death, which is sustained out to at least 6 months in most populations aged 12 years and older, including in older and frail populations. There is some decline in overall effectiveness noted in older adults (such as those 80 years of age and over) and residents in long term care homes in overall effectiveness over time, although protection against severe outcomes appears to be more durable than protection against infection .

 
COVID-19 vaccine would only be contraindicated if the component the individual is allergic to is also present in the influenza vaccine. Influenza vaccine and COVID-19 vaccine ingredients vary depending on the specific product. Refer to the respective product monographs for each vaccine or go to the BC Immunization Manual, Part 4 – Biological Products, COVID-19 and influenza vaccine pages for ingredient lists. 

With the exception of FluLaval® Tetra, which contains polysorbate 80, none of the influenza vaccines contain the potential allergens that are in the mRNA vaccines (polyethylene glycol [PEG]) or viral vector based vaccines (polysorbate 80). In addition, the COVID-19 vaccines do not contain any of the potential allergens found in the influenza vaccines (e.g., ovalbumin/egg protein, thimerosal, gelatin, antibiotics). These vaccines may have some other components in common but these are not known to be allergens, i.e., sucrose and various salts. 

Yes. With GBS, typically the biological basis would have been an immune mediated reaction to the antigens in the vaccine. As these antigens are not shared across influenza and COVID-19 vaccines, GBS following receipt of an influenza vaccine is not a contraindication to receiving a COVID-19 vaccine.

 

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Eligibility

In B.C., individuals 5 years of age and older are eligible to receive COVID-19 vaccination. 


Clinical trials are underway to determine if COVID-19 vaccines are safe and effective in infants and children under 5 years of age. ‎


More information on how to get vaccinated in B.C. can be found on the Getting a Vaccine page. 
 
 
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COVID-19 mRNA vaccines (adult/adolescent)

Additional information specific to the mRNA vaccines currently authorized for use in Canada can be found in the National Advisory Committee (NACI) Statement, Recommendations on the use of COVID-19 Vaccines, Appendices A & B.

Messenger RNA (mRNA) is the ‘blueprint’ that cells use to synthesize proteins required for our physiology. The two newly approved COVID-19 vaccines use mRNA contained inside a lipid nanoparticle (LNP) that contains the synthetic nucleotide sequences that codes for the SARS-CoV-2 spike protein. After injection, the LNP is taken up by immune system cells, and once inside a cell, the mRNA provides the instructions that allow the cell to manufacture the spike protein. Once manufactured, the spike protein exits the cell, and becomes anchored onto the cell's surface. The immune system is activated to recognize the spike protein as foreign and initiates an immune response. The mRNA is then cleared by the cell’s natural mRNA degradation process. The estimated half-life for mRNA after injection is about 8-10 hours before degradation by native RNases (enzymes that break up the mRNA) in the body; the expressed spike protein persists in the body for several days and during this time continues to stimulate the immune response. mRNA vaccines are not live vaccines and cannot cause infection in the host. The delivered mRNA does not replicate, and does not enter the cell nucleus or interact with or alter the recipient’s DNA. 1, 2, 3     

Several mRNA vaccines are under development for other infections including cytomegalovirus, human metapneumovirus, parainfluenza virus type 3, Zika and influenza viruses.  

Manufacturing of mRNA vaccines has been under development for a decade. The process is cell-free (does not use human or other animal cells) and does not use vectors (like other viruses) or animal products, preservatives or adjuvants. 


1. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. 2021 April 23 [cited 2021 April 28]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci.html

 

2. U.S. Food & Drug Administration [Internet]. Silver Spring (MD): U.S. Food & Drug Administration. 2020 meeting materials, vaccines and related biological products advisory committee December 10, 2020 meeting announcement. 2020 Dec 10 [cited 2021 Jan 5]. Available from: https://www.fda.gov/advisory-committees/advisory-committee-calendar/vaccines-and-related-biological-products-advisory-committee-december-10-2020-meeting-announcement

 

3. U.S. Food & Drug Administration [Internet]. Silver Spring (MD): U.S. Food & Drug Administration. 2020 meeting materials, vaccines and related biological products advisory committee December 17, 2020 meeting announcement. 2020 Dec 17 [cited 2021 Jan 5]. Available from: https://www.fda.gov/advisory-committees/advisory-committee-calendar/vaccines-and-related-biological-products-advisory-committee-december-17-2020-meeting-announcement

Efficacy

Pfizer-BioNTech COVID-19 vaccine 

The estimated vaccine efficacy at least 7 days after Dose 2 was 94.6% (95% CI: 89.9 to 97.3%), with 9 laboratory confirmed symptomatic COVID-19 cases identified among vaccine recipients (N=19,965) compared to 169 cases among placebo recipients (N=20,172). The vaccine efficacy at least 14 days after Dose 2 in this population was comparable (94.4%, 95% CI: 89.1 to 97.3%). 

When stratified by age, vaccine efficacy against COVID-19 from 7 days after Dose 2 was between 93.7% (>55 years) and 95.6% (16 to 55 years). In individuals ≥65 years of age, vaccine efficacy was 94.7% (95% CI: 66.7 to 99.9%). In participants ≥75 years of age, the observed vaccine efficacy was 100% compared to placebo (95% CI: -13.1 to 100.0%), however this must be interpreted with caution as there were few cases identified in this age group, accounting for the wide confidence intervals. The estimated vaccine efficacy against confirmed COVID-19 from 7 days after Dose 2 was greater than 91% (between 91.7% and 100.0%) in all subgroups stratified by "at risk" status (e.g., presence of 1 or more comorbidities). The estimated vaccine efficacy against confirmed COVID-19 illness from 7 days after Dose 2 was greater than 89% for all races (89.3 to 100%) and 94% for all ethnicities included in the sub-analysis (94.4 to 95.4%).1

Moderna COVID-19 vaccine 

The estimated vaccine efficacy at least 14 days after Dose 2 was 94.1% (95% CI: 89.3 to 96.8%), with 11 confirmed COVID-19 cases identified among vaccine recipients (n= 14,134) compared to 185 confirmed COVID-19 cases among placebo recipients (n= 14,073). 

When stratified by age, vaccine efficacy against COVID-19 from 14 days after Dose 2 for those 18 to < 65 years of age was 95.6% (95% CI: 90.6 to 97.9%). For those > 65 years of age, vaccine efficacy was 86.4% (95% CI: 61.4 to 95.2%). For those > 75 years of age, vaccine efficacy was 100% however; this must be interpreted with caution as there were few cases identified in this age group.2

‎For both mRNA vaccines, SARS-CoV-2 binding and neutralizing antibodies were both induced by one dose of the vaccine and boosted by the second dose of the vaccine. Immunity after the first dose was seen beginning at around day 10 with the Pfizer vaccine and day 14 following the Moderna vaccine. Maximal immune response was seen 7 days after the second dose for each vaccine. 1, 2

 

‎1. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. Appendix A. 2021 Jan 12 [cited 2021 Jan 13]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines.html


2. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. Appendix B. 2021 Jan 12 [cited 2021 Jan 13]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines.html


Dosing and scheduling

Refer to the BC Immunization Manual Part 4 - Biological Products, COVID-19 vaccines for complete information on the COVID-19 mRNA vaccines prior to administration.

For optimal response, immunizers should observe recommended intervals as much as possible, however, doses given earlier than recommended may still be considered valid and need not be repeated if minimum intervals are observed. The recommended minimum intervals between doses for the COVID-19 mRNA vaccines are as follows:

  • Pfizer-BioNTech: 18 days 
  • Moderna: 21 days

NACI recommends that the vaccine series be completed with the same COVID-19 vaccine product. However, the spike proteins that encode the authorized mRNA vaccines have the same sequence and are stabilized in the same manner to remain in the pre-fusion confirmation, though other vaccine components like the lipid nanoparticle may be different.

 

If the vaccine product used for a previous dose is not known, attempts should be made to identify which vaccine was given for the first dose in order to give the same product for the second dose. If the same product is not readily available, the vaccine series can only be complelted with a similar type of COVID-19 vaccine (i.e., mRNA vaccine). Readily available means it is easily available at the time of vaccination without delay or vaccine wastage. Such a series should be considered as valid, without need to restart a two dose series with a new product. 


On June 1st 2021, NACI recommended that individuals who received a first dose of of the AstraZeneca or COVISHIELD vaccine could receive an mRNA vaccine for their second dose, unless there are contraindications to the mRNA vaccine.

1. Pfizer Canada ULC.  Pfizer-BioNTech COVID-19 Vaccine Product Monograph [Internet]. 2020 Dec 9 [cited 2021 February 19]. 26 p. Available from: https://covid-vaccine.canada.ca/info/pdf/pfizer-biontech-covid-19-vaccine-pm1-en.pdf

 

2. Moderna Therapeutics Inc. Moderna COVID-19 Vaccine  Product Monograph [Internet]. 2020 Dec 23 [cited 2021 Jan 5]. 19 p. Available from: https://www.modernacovid19global.com/ca/product-monograph.pdf

Administration

Yes. A 21-gauge needle or narrower is recommended to prevent a larger opening in the vial stopper that may allow vaccine to leak.1

Yes. After adding the diluent into the vaccine vial, withdraw 1.8 mL of air from the vaccine vial into the empty diluent syringe prior to removing the needle and attached syringe from the vial.  This will prevent loss of vaccine from the vial through forceful expulsion under pressure.1 ‎

 

An additional dose can be withdrawn in its entirety, if the volume of residual vaccine allows, or constituted from up to three separate vials with residual vaccine, after withdrawal of the full number of labelled doses from the Pfizer (labelled 6 doses of 0.3 mL each/vial) or Moderna (labelled 10 doses of 0.5 mL each/vial or 14 doses of 0.5 mL each/vial for the US-labelled product) vaccines.

 

Following withdrawal of all available doses from each vial, the residual vaccine from up to three vials can be withdrawn into the same syringe to constitute a full dose provided the vials are from the same manufacturer and have the same lot number. More information can be found in the BC Immunization Manual, Part 4 – Biological Products: Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines – Addendum: Pooling residual vaccine from up to three vials to constitute an extra dose.

 

Withdrawal of even 6 doses from a single vial of the Pfizer-BioNTech vaccine is dependent, in part, on the type of syringes or needles used to withdraw the vaccine from the vial. Low dead-volume syringes and/or needles should be used if available, as standard syringes and needles may not facilitate the extraction of the sixth dose from a single vial.  Similarly for Moderna, the withdrawal of a complete 0.5 mL dose after 10 or 14 doses have been removed from the vial is dependent, in part, on the type of syringes and needles, and low dead-volume syringes and/or needles may be needed to extract an additional dose.

Pain at the injection site is very common after the administration of the currently authorized COVID-19 mRNA vaccines, with more than 80% of recipients experiencing local injection site pain. Redness and swelling are also common.  Delayed local reactions including pain, redness, swelling, and occasionally pruritus, were observed in the Moderna clinical trials in about 1% of vaccine recipients, with onset on or after day 8 following vaccination. These delayed reactions were more likely to occur following the first dose than the second dose, and are thought to represent dermal hypersensitivity, typically resolving after 4-5 days. Vaccine recipients who have experienced these delayed local reactions have safely received the second dose.2, 3  These events are not reportable unless they meet the reporting criteria outlined in the BC Immunization Manual, Part 5: Adverse Events Following Immunization. 

 

1. Pfizer-BioNTech COVID-19 Vaccine [Internet}. Kirkland (QC): Pfizer Canada ULC; c2021. Dosing and administration; 2020 Dec [cited 2020 Dec 22]. Available from: https://www.cvdvaccine.ca/dosing-and-administration.


2. Moderna. mRNA-1273 Sponsor Briefing Document [Internet]. Silver Spring (MD): FDA, Vaccines and Related Biological Products Advisory Committee; 2020 Dec 17 [cited 2021 February 22]. 83p. Available from: https://www.fda.gov/media/144452/download


3. Blumenthal KG, Freeman EE, Saff RR, et al. Delayed Large Local Reactions to mRNA1273 Vaccine against SARS-CoV-2. N Engl J Med. Published online March 3, 2021:NEJMc2102131. doi:10.1056/NEJMc2102131

Contraindications and precautions

Severe immediate allergic reactions such as anaphylaxis 

have been reported to be very rare following mRNA vaccination. As of October 22, 2021, NACI has made recommendations based on recent studies demonstrating that individuals who experienced anaphylaxis following their first dose of mRNA vaccine, were able to receive their second dose of mRNA vaccine with either mild or no side effects. NACI recommends that these individuals can safely receive future doses of mRNA vaccine provided there is:

  • consultation with an allergist or another appropriate physician before receiving future doses of a COVID-19 mRNA vaccine
  • a controlled setting where the vaccine can be administered with someone available who is experienced in managing anaphylaxis
  • an observation period of at least 30 minutes after vaccination (the normal observation period for people who have not experienced a severe immediate allergic reaction after vaccination is 15 minutes).
For a list of components in the vaccine and packaging consult the respective COVID-19 mRNA vaccine product monographs found at:

Both of the authorized COVID-19 mRNA vaccines in Canada contain polyethylene glycol (PEG) which can be found in various products such as: bowel preparation products for colonoscopy, laxatives, cough syrup, cosmetics, contact lens care solutions, skin care products and as an additive in some food and drinks. No cases of anaphylaxis to PEG in foods and drinks have been reported. ‎

 

In situations of suspected hypersensitivity or non-anaphylactic allergy to COVID-19 vaccine components, mRNA vaccination should be administered in a controlled setting with expertise and equipment to manage anaphylaxis, with an extended period of observation post-vaccination of at least 30 minutes.

Myocarditis is an inflammation of the heart muscle; if it is accompanied by pericarditis, an inflammation of the thin tissue surrounding the heart (the pericardium), it is referred to as myopericarditis. Symptoms can include shortness of breath, chest pain, or the feeling of a rapid or abnormal heart rhythm. Symptoms can be accompanied by abnormal tests (e.g., electrocardiogram, serum troponins, echocardiogram). These are inflammatory disorders of the outer lining of the heart and heart muscle, and occur for a variety of reasons including in association with viral infections.

As such, myocarditis can occur as a complication of COVID-19 infection. In Israel, COVID-19 infection has been estimated to cause myocarditis at a rate of 11 events per 100,000 persons among individuals aged 16 years and older. A retrospective study from the US found myocarditis (or pericarditis or myopericarditis) rates after primary COVID-19 infection to be as high as 45 cases per 100,000 patients in young males aged 12-17 years.  


Myocarditis/pericarditis following COVID-19 mRNA vaccines remains a rare adverse event following immunization (defined by the Canadian Immunization Guide as occurring at a frequency of 1 per 10,000 cases to less than 1 per 1,000 cases), even among the age groups where the highest rates of this event have been observed.17 Canadian data continue to show that with the primary series, the incidence of myocarditis is rare with either mRNA vaccine, but higher following the Moderna 100 mcg vaccine compared to the Pfizer-BioNTech 30 mcg vaccine. In Canada, as of November 12, 2021, the overall reported rate of myocarditis/pericarditis was 3.0 per 100,000 doses administered following any dose of the Moderna 100 mcg vaccine compared to 1.9 per 100,000 doses administered following any dose of the Pfizer-BioNTech 30 mcg vaccine. The reported rates of myocarditis/pericarditis among males 18-29 years after the second vaccine dose were 15.9 per 100,000 for the Moderna 100 mcg vaccine and 2.6 per 100,000 for the Pfizer-BioNTech 30 mcg vaccine. These events are reported more frequently after the second dose and have been observed mostly in males 12-29 years of age, usually within a week of vaccination. Most cases have been mild and resolved quickly. 

Most cases recover fully with conservative treatment, with no serious outcomes. In BC, we have ensured that health care providers are aware of this observation and the possibility of it being causally linked to the vaccine, and how to diagnose and report this event when it occurs after mRNA vaccine. This is an emerging safety signal and will need to be studied further. 

In B.C., the Pfizer-BioNTech vaccine is preferentially recommended if available, for the primary series in individuals 12-29 years of age. While the risk of myocarditis and pericarditis continues to be a rare event following mRNA vaccination, there is a differentially lower risk of myocarditis and pericarditis following vaccination with Pfizer-BioNTech in comparison to Moderna. However, if the Pfizer-BioNTech vaccine is unavailable, or upon client request, the Moderna COVID-19 vaccine can be used provided informed consent includes the elevated risk of myocarditis associated with this vaccine. Individuals aged 30 and above should receive either mRNA vaccine (Pfizer-BioNTech or Moderna).

The second dose of COVID-19 mRNA vaccine should be deferred in those who experienced a physician-diagnosed myocarditis or pericarditis event following the first dose with no other cause identified, until further information about the risk of recurrence is available. Deferral is not required for those with a prior history of myocarditis or pericarditis that is unrelated to COVID-19 mRNA vaccines and are no longer being followed by a medical professional for heart issues.

Vaccine storage and handling

‎As neither mRNA vaccine contains preservatives to prevent microbial contamination, the Pfizer-BioNTech vaccine must be used within 6 hours of dilution and the Moderna vaccine must be used within 24 hours of first puncture to the vial.

Pfizer-BioNTech: https://www.cvdvaccine.ca/

Moderna: https://www.modernacovid19global.com/ca/


For more information specific to receiving and handling the Pfizer-BioNTech and Moderna vaccines, refer to the BC Immunization Manual, Appendix E - Management of Biologicals, Guidance for Receiving and Handling the Pfizer-BioNTech COVID-19 mRNA vaccine (including dry ice procedures) and Guidance for Receiving and Handling the Moderna COVID-19 mRNA Vaccine. Additional information, including standard operating procedures can be found on the COVID-19 Immunize BC Operations Centre: Standard Operating Procedures page. 

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Booster doses

While vaccine effectiveness (VE) against SARS-CoV-2 infection following the completion of a primary series was originally demonstrated to be high (>90%) against the original strain and earlier variants (e.g., Delta), VE against Omicron infection and symptomatic disease after an mRNA primary series is substantially lower and decreases with time from the second dose; protection is minimal by six months since the second dose in adults. 1 

VE in adults against infection/symptomatic disease for Omicron from a booster of mRNA vaccine is approximately 65% and in most studies, decreases over time since vaccination. Vaccine protection in adults against severe disease and hospitalization due to COVID-19 has been more durable than protection against symptomatic disease or infection, and is approximately 10 to 20% higher following a third dose (or first booster) compared to those who have only completed a primary series, reaching approximately 90% or more. There are emerging data on the VE of a booster dose against infection/symptomatic disease over time in adolescents showing similar trends as observed in adults.

Given the resurgence in cases due to the increased transmissibility of the Omicron BA.2 sub-lineage and the lifting of public health measures, NACI has updated the recommendations on the use of a first booster dose of COVID-19 vaccine in Canada which may help to further reduce infections and severe disease. 

With NACI’s updated recommendations, a first booster dose may now be offered to everyone 12 years of age and over. NACI has also strengthened their recommendation for the first booster dose from “discretionary” to “strong” in adults 18-49 years of age and for adolescents who may be at higher risk of severe outcomes from COVID-19 infection (i.e., adolescents with an underlying medical condition that puts them at high risk of severe illness due to COVID-19,  residents of congregate living settings and racialized and/or marginalized communities disproportionately affected by COVID-19).  NACI has also added a new “discretionary” recommendation for a first booster dose in all other adolescents. 

 

‎To date, most studies examining the duration of protection have been based on manufacturer-recommended dosing intervals of 3 or 4 weeks between the first and second doses for mRNA vaccines. In B.C. and Quebec, data show that extended intervals between doses result in increased vaccine effectiveness against SARS-CoV-2 infection and COVID-19 related hospitalizations, when compared to shorter intervals. In addition, the emergence of the Delta variant and subsequently the Omicron variant, have resulted in an increase in cases seen during the fourth wave of the pandemic.  Simultaneously, breakthrough cases have been observed in vaccinated individuals. It is difficult to ascertain whether this is due to waning protection in these individuals or if this is attributable to these individuals living within a community with lower vaccination levels.  Furthermore, emerging evidence suggests vaccine effectiveness against infection and symptomatic disease due to Omicron after an mRNA primary vaccine series is lower compared to effectiveness against previous variants of concern. Preliminary, non-peer reviewed Canadian data, using a test-negative study design from Ontario, estimated vaccine effectiveness against symptomatic Omicron infection 7 or more days after a third dose with any mRNA vaccine was 61%, compared to unvaccinated individuals. Vaccine effectiveness against severe outcomes caused by Omicron remained high (~82-86%) in individuals with 2 doses, but increased to 95% after a third dose. 2

 
In B.C., a booster dose of a COVID-19 mRNA vaccine is recommended for those who are 12 years of age and older at least 6 months after completion of the primary series. Either of the Moderna or Pfizer-BioNTech COVID-19 vaccines may be used as a booster dose regardless of which COVID-19 vaccine was used in the primary series. However, one mRNA vaccine may be preferentially recommended over the other based on age and immunocompetence.

The Pfizer-BioNTech COVID-19 vaccine is preferred for the booster dose in immuncompetent individuals 12-29 years of age due to the lower risk of myocarditis/pericarditis with this vaccine. However, if the Pfizer-BioNTech vaccine is unavailable, or upon client request, the Moderna COVID-19 vaccine can be used provided informed consent includes the elevated risk of myocarditis/pericarditis associated with this product. Individuals aged 30 and above should receive either mRNA vaccine (Pfizer-BioNTech or Moderna).

For individuals 12-17 years of age who are moderately to severely immunosuppressed, the Pfizer-BioNTech COVID-19 vaccine is preferred for the booster dose as there currently are no data on the use of the Moderna vaccine as a booster dose in this population.  However, the Moderna COVID-19 vaccine is preferred for the booster dose in those 18 years of age and older who are moderately to severely immunosuppressed.

Refer to the BC Immunization Manual, Part 4 - Biological Products, COVID-19 Vaccines, COVID-19 Vaccine Eligibility for more information.

The recommended interval for a booster dose is at least 6 months after the primary series has been completed. Evidence from clinical trials showed a robust immune response in individuals who received a booster dose at least 6 months after completion of a primary series.3 


For those who received a 1-dose primary series of the Janssen COVID-19 vaccine,  a booster dose of mRNA vaccine is recommended at least 2 months after completion of the primary series. 

 

The minimum interval between a COVID-19 vaccine primary series and a booster dose is 8 weeks. Although the recommended interval between a COVID-19 vaccine primary series and a booster dose is 6 months, the 8 week minimum interval may be applied to a minority of individuals for practical reasons. Clients requesting a shorter interval should be informed that this is not optimal for protection, but their request for an earlier dose should be granted without need for MHO approval, provided the minimum interval between doses has been observed.


Immunogenicity studies indicate that booster doses of mRNA vaccines given at 3 or more months after the primary series elicit a robust immune response against the wild type Wuhan strain and circulating variants of concern, with antibody titres often measuring higher after the booster dose than after the primary series. In addition, a longer interval between completion of the primary series and booster dose may result in higher antibody titres.4


Individuals who wish to receive their booster dose earlier than the recommended 6 month interval can contact the BC Government's Get Vaccinated system at 1-833-838-2323 to book an appointment.

A booster dose given with Pfizer-BioNTech vaccine is given as a full dose of 0.3 mL (30 mcg), the same as a dose within a primary series. However, a booster administered with Moderna vaccine will be given as a standard dose of 0.5 mL (100 mcg) to certain populations (e.g., individuals ≥ 70 years of age), while other individuals will receive a half dose of 0.25 mL (50 mcg). However, individuals less than 70 years of age who are moderately to severely immunosuppressed may receive the 0.5 mL (100 mcg) dose of Moderna vaccine upon requiest.  Refer to the BC Immunization Manual, Part 4 - Biological Products, COVID-19 Vaccines for further details.

 

Moderna filed submissions to Health Canada for regulatory approval for a booster dose at half the current dosage (i.e., a 50 mcg [0.25 mL] booster dose vs. 100 mcg [0.5 mL] primary series dose). However, on October 29, 2021, NACI recommended that older adults may benefit from a 100 mcg (0.5 mL) dose of Moderna vaccine as a way to bolster the immune response from a booster dose. 


In B.C. it’s recommended that residents of long term care (LTC), assisted living and independent living facilities, alternate level of care clients awaiting placement in LTC and individuals 70 years of age and older who receive Moderna as a booster dose, should receive a full 100 mcg (0.5 mL) dose. All other individuals eligible for a booster dose that receive Moderna as their booster dose will receive a 50 mcg (0.25 mL) dose.3 However, individuals  less than 70 years of age who are moderately to severely immunosuppressed may receive the 100 mcg (0.5 mL) dose of Moderna vaccine upon request.

If an eligible individual is receiving Pfizer-BioNTech vaccine as their booster, the dose is the standard 0.3 mL dose.

In B.C., all individuals 12 years of age and older are eligible for a booster dose, including those who received a 3-dose primary series such as individuals who are moderately to severely immunosuppressed.

Initial results from studies that were sponsored by the manufacturers of mRNA vaccines suggest that reactogenicity from a third dose is similar to that from a second dose. However, these were studies of a small sample size (less than 350 participants in each study) with a short duration of follow-up.3

It is not yet known what the rate of myocarditis and pericarditis is after a booster dose with mRNA vaccine. Early data from Israel’s booster dose program show the rate following a booster as lower than with the second dose, but still increased when compared to rates following the first dose. Further studies into this are ongoing.

Pregnancy is a higher risk period for complications from COVID-19 infection, and pregnant people are more likely to be hospitalized and admitted to intensive care compared to their non-pregnant age-matched peers.  

Optimizing immunity against COVID-19 during pregnancy is desirable because serious illness during pregnancy can put both the pregnant person and the fetus at risk and may result in preterm birth, still birth or Caesarian section. COVID-19 immunization during pregnancy is safe for the pregnant person and for the fetus. No specific safety signals have been detected related to pregnancy.

Although, the primary indication for administration of COVID-19 vaccination is for maternal protection, IgG antibodies from the pregnant person are transferred to the fetus. This provides ‘passive immunity’ to the newborn, which may reduce the risk of infection for the infant during their first several months of life.

As there is a limited opportunity to provide protection during pregnancy, an earlier window for receipt of the booster dose has been enabled through the ImmsBC booking system. To receive a COVID-19 vaccine booster 8 weeks after their second dose, pregnant individuals will need to call the central call line (1-833-838- 2323) to book their appointment.

1. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. National Advisory Committee on Immunization (NACI). Updated Guidance on a first booster dose of COVID-19 vaccines in Canada. 2022 April 12 [cited 2022 Apr 14]. Available from: https://www.canada.ca/content/dam/phac-aspc/documents/services/immunization/national-advisory-committee-on-immunization-naci/naci-guidance-first-booster-dose-covid-19-vaccines.pdf


2.  Kwong, J. Effectiveness of COVID-19 vaccines over time in Ontario. In: How long does immunity to COVID-19 last? (presentation slides from COVID-19 Immunity Task Force &
CanCOVID seminar series January 24, 2022) [Internet]. Ontario: COVID-19 Immunity Task Force; 2022 Jan 24 [cited 2022 Jan 26]. Available from: https://cancovid.ca/event/covid-19-immunity-task-force-citf-cancovid-seminar-series-research-results-implications/

3. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Interim guidance on booster COVID-19 vaccine doses in Canada. 2021 October 29 [cited 2021 November 22] Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines/statement-guidance-booster-doses.html

4. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. National Advisory Committee on Immunization (NACI) Guidance on booster COVID-19 vaccine doses in Canada. 2021 December 3 [cited 2022 Mar 31]. Available from:  https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/guidance-booster-covid-19-vaccine-doses.html

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Second booster dose

Many areas in Canada are seeing an increase in COVID-19 activity and cases. The easing of restrictions, the more transmissible BA.2 variant and waning immunity may have contributed to increases in transmission.

During the Omicron wave in Canada, the incidence of severe outcomes, including hospitalization and death, was highest among adults 80 years of age and older, followed by adults 70 to 79 years of age. Adults younger than 70 years of age in or from First Nations, Inuit, and Métis communities are at increased risk for severe disease due to a variety of interconnected factors, including underlying medical conditions and potentially limited access to health care. 

Studies show that with a booster, vaccine effectiveness in adults against infection from Omicron is approximately 60% but decreases over time. However, protection in adults against severe illness and hospitalization due to COVID-19 from a primary series remains good and is further improved with a booster dose reaching vaccine effectiveness of approximately 90% or more. Emerging evidence in adolescents on the effectiveness of a booster dose against infection over time shows trends similar to those observed in adults.

While evidence indicates that the COVID-19 vaccines used in Canada are very effective at preventing severe illness, hospitalization and death from COVID-19, there is limited evidence on the duration of protection from a first booster dose, with a few studies suggesting a decrease in protection over time, possibly from 6 months onwards. Preliminary data indicates that a second booster dose provides additional protection compared to a first booster, including against severe disease.  

NACI recommends the second COVID-19 booster doses for older adults in the context of protection against severe disease potentially decreasing over time following the first booster dose, and/or risk of immune evasion by the highly transmissible variants of concern which can cause severe disease. 
As of April 5th 2022, a second booster dose of a COVID-19 mRNA vaccine is recommended and should be offered to the following individuals:
  • Residents of LTC and alternate level of care clients awaiting placement in LTC
  • Residents of assisted living facilities 70 years of age and older (Indigenous persons 55 years of age and older)
  • Individuals 80 years of age and older in the community
A second booster dose of a COVID-19 mRNA vaccine may be offered to individuals 70-79 years of age (Indigenous persons 55-79 years of age) in the community.

Information on the second booster dose can be found in the BC Immunization Manual Part 4 – COVID-19 Vaccine Eligibility

The National Advisory Committee on Immunization (NACI) provides technical advice to  the Public Health Agency of Canada (PHAC) for use by provinces and territories and health care providers. NACI makes two types of recommendations - strong recommendations and discretionary recommendations. A strong recommendation uses the words "should/should not be offered" while a discretionary recommendation uses the words "may/may not be offered."

 

A strong recommendation is one that applies to most individuals in a population unless a compelling alternative is available. A discretionary recommendation means that the vaccine may be considered for individuals in a population, but that the decision should be made considering factors such as individual benefits and risks, or local epidemiology.

The recommended interval between the first and second booster dose is 6 months. The minimum interval is 4 months and may be applied for a minority of individuals for practical reasons, such as operational efficiency when immunizing at care facilities.  Clients
requesting a shorter interval should be informed that this is not optimal for protection, but their request for an earlier dose should be granted without need for MHO approval, provided the minimum interval between doses has been observed.
Individuals who are eligible to receive a 2nd booster dose and who experienced a recent SARS-CoV-2 infection may defer for three months after symptoms started or testing positive (if they experienced no symptoms) provided it is at least six months after receiving their 1st booster dose, whichever interval is longer. 

However, the 3-month interval following SARS-CoV-2 infection is a suggested interval based on immunological principles and expert opinion, and may change as evidence on COVID-19, variants of concern (VOC), and COVID-19 vaccines emerge. When considering whether or not to administer vaccine doses following the suggested 3-month interval, biological and social risk factors for exposure (e.g., local epidemiology, circulation of VOCs, living settings) and severe disease should also be taken into account. These intervals are to be used as a guide and clinical discretion should be applied.  
The 2nd booster may be given with the Pfizer-BioNTech (30 mcg), Moderna (50 mcg) or the Novavax vaccines. The Novavax vaccine would be used for those who cannot or refuse to receive an mRNA vaccine. 

The recommended dose for the Moderna vaccine is 50 mcg (0.25 mL) for the second booster which differs from the 100 mcg (0.5 mL) recommendation for the first booster. 
At this time, evidence is evolving that will help inform whether ongoing repeated boosting for COVID-19 is needed. The Government of Canada continues to monitor the impact of booster doses against emerging variants based on immunologic responses and protection against infection and severe disease.

While not recommended at this time, second booster dose immunization programs for other high-risk groups and the general public may be needed if data suggest concerning COVID-19 trends, such as severe disease in younger age groups or the emergence of new variants of concern.

Individuals who are moderately to severely immunocompromised are recommended to receive a three dose primary series, followed by a first booster dose 6 months following the completion of the 3-dose primary series (for a total of four doses). While there are not specific second dose booster recommendations for immunocompromised individuals at this time, second booster dose immunization programs for immunocompromised individuals and other high-risk groups as well as the general public may be needed at a later date if data suggest concerning COVID-19 trends, such as the emergence of new variants of concern.

 
1. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. National Advisory Committee on Immunization (NACI).  Initial guidance on a second booster dose of COVID-19 vaccines in Canada April 5, 2022

2. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. National Advisory Committee on Immunization (NACI). Summary of NACI statement of April 5, 2022 

3. Public Health Agency of Canada. Ottawa (ON): Vaccine Confidence Info Bulletin, Volume 2, Issue 4, April 2022

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COVID-19 mRNA vaccines for children (5-11 years)

Refer to the BC Immunization Manual, Part 4 – Biological Products, COVID-19 vaccines for complete information on the COVID-19 mRNA vaccines prior to administration.

On November 19, 2021 Health Canada approved the Pfizer-BioNTech COVID-19 vaccine (COMIRNATY®, 10 mcg) for use in children 5-11 years of age. Moderna's COVID-19 vaccine (SPIKEVAXTM, 50 mcg) was approved for use in children 6-11 years of age on March 17, 2022. The National Advisory Committee on Immunization (NACI) recommends that a complete series of an mRNA COVID-19 vaccine should be offered to children in the authorized age group who do not have contraindications to the vaccine, with a dosing interval of at least 8 weeks between the first and second dose.  For children 6-11 years of age, the Moderna vaccine (50 mcg) may be offered as an alternative to the Pfizer-BioNTech vaccine (10 mcg); however, the Pfizer-BioNTech vaccine is preferred to the Moderna vaccine to start or continue the primary vaccine series.
While most children do not become severely ill with COVID-19 disease, rarely some children may develop severe COVID-19 disease and require hospitalization. 

Children are also at risk of developing multisystem inflammatory syndrome in children (MIS-C), following infection with the SARS-CoV-2 virus. MIS-C is a rare but serious event that can occur several weeks following infection. As of March 12, 2022, there have been a total of 28 cases of MIS-C in BC with a median age of 9 years (range 1 to 16).1

Children may also be at risk of a post COVID-19 condition known as long COVID or post-acute COVID-19 syndrome. While evidence is limited in pediatric populations, current evidence suggests the risk is lower in children compared to older age groups.

The Delta and Omicron variants may pose a higher risk of infection for children due to their increased transmissibility, although the risk of severe disease in children does not appear to be increased with these variants. 

Though children were underrepresented in COVID-19 cases through the first three waves in Canada, this fourth wave is having a greater impact on those under 12 years of age. That is because this age group has not yet been able to be vaccinated and community transmission has continued with the gradual reopening of society. As of mid-November of 2021, children 5-11 years of age had the highest rate of COVID-19 cases across all age groups, although hospitalization rates have remained low.2  

Throughout the pandemic, children have experienced social isolation, disruption to schooling and extra-curricular activities, which have had profound impacts on the mental and physical well-being of children and their families. These harms can disproportionately affect some children and families and may further exacerbate social inequities among some groups, including racialized and Indigenous communities, refugees and other newcomers to Canada, persons living in low-income settings, as well as children with disabilities.3 

In addition, broad vaccination for COVID-19 is a critical tool to best protect everyone, especially those at highest risk, from severe illness and death. While following current public health measures, individuals who are fully vaccinated can safely resume many activities that they did prior to the pandemic.
 

As per the COVID-19 Situation Report Week 10 (March 12, 2022), since the beginning of the pandemic there have been 29,382

COVID-19 cases resulting in 365 hospitalizations, 29 ICU admissions and 2 deaths in children less than 10 years of age. There have been 35,274 COVID-19 cases in older children and adolescents 10-19 years of age which has led to 283 hospitalizations, 35 ICU admissions and zero deaths. There have been a total of 28 confirmed cases of multi-system inflammatory syndrome in children and adolescents (MIS-C) in BC, with a median age of 9 years (range 1-16). 


More information about COVID-19 cases in BC can be found on the BCCDC BC COVID-19 Data page.

Clinical trial data indicate that the pediatric formulation of the Pfizer-BioNTech COVID-19 vaccine (10 mcg) produces a good immune response in children 5-11 years of age, similar to the response seen in young adults 16-25 years of age who received the adolescent/adult formulation (30 mcg). Preliminary efficacy of the 10 mcg dose of vaccine against symptomatic COVID-19 in children 5 to 11 years of age was estimated to be 90.7%. 


In clinical trials, the 50 mcg dose of Moderna vaccine produced a good immune response in children 6-11 years of age that was similar to the response produced in 18-25 year olds who received a 100 mcg dose of the vaccine. The preliminary efficacy of the 50 mcg dose of Moderna vaccine in children 6-11 years of age was 88% against confirmed symptomatic COVID-19 from 14 days after the first dose.

 

Dose escalation studies were conducted in phase 1 clinical trials to establish the appropriate dose on the basis of reactogenicity and immunogenicity of the administered doses. Based on these studies, a dose of 10 mcg was selected for the Pfizer-BioNTech pediatric vaccine4 (one third of the adult/adolescent dose) while a dose of 50 mcg was selected for the Moderna vaccine (one half of the adult/ adolescent dose). 

 

No allergic events or anaphylactic reactions were reported after either dose. No serious adverse events (SAE) related to the vaccine, no cases of multisystem inflammatory syndrome in children (MIS-C), myocarditis/pericarditis or deaths were reported. Due to the size of the clinical trials, it is unlikely that any adverse events occurring at a frequency less often than 1 in 1,000 would be detected.

 
Phase 2/3 of clinical trial data evaluated the frequency of adverse events in children aged 5-11 years for the pediatric Pfizer-BioNTech vaccine  (10 mcg) and children 6-11 years for the Moderna vaccine (50 mcg). Local reactions including pain, redness and swelling were very common, appearing 1-2 days after any dose and typically resolved within 1-3 days. Systemic events were mild or moderate in severity and included fatigue, headache, muscle pain, chills, fever and joint pain. Onset of systemic events was within 1-4 days after vaccine receipt with a median duration of 1 day.
 
No cases of myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the lining around the heart) were observed in the clinical trials of the COVID-19 mRNA vaccines in children 5-11 years of age. However, due to the number of study participants in the clinical trials, adverse events occurring at a frequency of less than 1 in 1,000 may not have been detected.

Cases of myocarditis and pericarditis  have been reported following vaccination with COVID-19 mRNA vaccines in Canada and internationally among individuals aged 12 years and older who received the 30 mcg formulation of the Pfizer-BioNTech COVID-19 vaccine or 100 mcg formulation of the Moderna COVID-19 vaccine; however, the risk is considered rare. 

Cases of myocarditis/pericarditis following COVID-19 mRNA vaccination occur most commonly in adolescents and young adults (12 to 30 years of age). It usually occurs within a week of vaccination and is more common:
  • after the second dose
  • in males than females
  • after receipt of the Moderna vaccine than the Pfizer-BioNTech vaccine.
The highest rate of myocarditis reported in Canada in association with the Pfizer COVID-19 mRNA vaccine has been for males aged 12 to 17 years following the 2nd dose, with about 7 cases per 100,000 doses. In both Canada and the US, no deaths attributed to the COVID-19 mRNA vaccine-related myocarditis have been identified in adolescents or young adults. 

Data from the US suggest the risk of myocarditis/pericarditis following mRNA COVID-19 vaccination may be higher in older adolescents aged 16-17 years compared to younger adolescents aged 12-15 years.5 In addition, surveillance data suggests that the risk of myocarditis/pericarditis within 7 days of receipt of the second dose of the pediatric Pfizer-BioNTech vaccine may be substantially lower in 5-11 year old males compared to adolescents who received the adult/adolescent Pfizer-BioNTech vaccine.6 

Symptoms of myocarditis/pericarditis can include shortness of breath, chest pain, or the feeling of a rapid or abnormal heart rhythm. Symptoms can be accompanied by abnormal test results (e.g., electrocardiogram, serum troponins, echocardiogram).7  Available data indicate that most individuals affected have responded well to conservative therapy and have recovered quickly.3

Emerging Canadian safety surveillance data suggest an extended interval between the first and second dose may reduce the risk of myocarditis/pericarditis associated with the second dose of an mRNA COVID-19 vaccine. For children 5-11 years of age the recommended interval between first and second dose is 8 weeks.3

Myocarditis following mRNA COVID-19 vaccination tends to have a similar epidemiologic profile to classic myocarditis (unrelated to COVID-19), as it occurs more commonly in adolescents and young adult males. Classic myocarditis is less common in younger children 5-11 years of age.5

It is unknown whether myocarditis/pericarditis will occur after the lower doses of mRNA present within pediatric COVID-19 vaccines for children 5-11 years of age.3

A Children’s Hospital of Philadelphia article states, “This situation may cause some parents to consider taking a “wait and see” approach, delaying their child’s vaccination until more doses have been administered. However, what many parents don’t realize is that in teens and young adults — the group with the highest occurrence of this side effect — the risk of developing myocarditis is greater following natural infection”. The article included the following estimates for myocarditis following COVID-19 mRNA vaccination compared to myocarditis following COVID-19 infection:

Of 100,000 males aged 16 to 29 years of age, approximately 5 would develop myocarditis after COVID-19 mRNA vaccination and about 59 would develop myocarditis after COVID-19 infection.

If we consider 100,000 females aged 16 to 29, 1 would develop myocarditis after vaccination and about 39 would develop myocarditis after COVID-19 infection.

As such, the risk of experiencing myocarditis is greater in an unvaccinated person than a vaccinated person. Therefore, opting to delay or forgo vaccination to avoid myocarditis is opting to take the risk of developing COVID-19 infection, which could put the child at greater risk of experiencing myocarditis.8  
 
Yes. General immunization guidelines support the administration of a COVID-19 vaccine before, at the same visit, or after other vaccines at a different injection site(s) without regard to timing (this includes live and inactivated vaccines). If a client is due for more than one vaccine, providers are encouraged to offer all of the vaccines at the same visit. Concomitant administration of all recommended vaccines is important because it increases the probability that people will be fully vaccinated. It is also an important part of immunization practice if a healthcare provider is uncertain that a patient will return for additional doses of vaccine. This recommendation also aligns with the US CDC guidance.

While co-administration of COVID-19 vaccines with routine childhood vaccines has not been studied,  a recent study evaluating the safety and immunogenicity of concomitant administration of COVID-19 vaccines with seasonal influenza vaccine in adults saw no safety concerns and antibody responses to both vaccines were maintained.9  NACI suggests that concomitant administration may contribute to erroneous attribution of an AEFI to a vaccine and it may preferentially be avoided; however, it may be warranted on an individual basis in some circumstances at the clinical discretion of the healthcare provider.3
 
 

‎Tromethamine (Tris or trometamol) is used as a buffer in vaccines and medications, including those for use in children, to improve stability and prevent pH fluctuations in the solution. Tromethamine is widely used in several medications for topical, enteral or parenteral administration. It is also used in cosmetics as an emulsifier.10 No safety concerns have been identified with tromethamine. While tromethamine has been identified as a potential allergen, a review of existing evidence did not identify any cases of allergic reactions to tromethamine in children.3 Tromethamine has been identified as a potentially allergenic excipient and is present in the pediatric Pfizer-BioNTech and Moderna COVID-19 vaccines. However, there is increasing evidence that tromethamine is not the culprit excipient and/or the reactions are not IgE-mediated. This remains under investigation.11 

Even though severe outcomes from COVID-19 in children are uncommon, they can occur.  Vaccinating children helps keep them safe, and helps them keep vulnerable people in their community such as; older adults, younger children and infants and people with other health conditions safe as well.


The following are additional key messages to share with parents about COVID-19 vaccination for children aged 5-11:

  • Without vaccination, all children will likely contract the virus at some point2
  • The benefits of vaccination will help protect their child from COVID-19 infection
  • Children who are infected with COVID-19 can develop multisystem inflammatory syndrome in children (MIS-C), a rare but serious condition. Although uncommon, as of March 12, 2022, there have been 28 cases of MIS-C in BC related to COVID-19 infection with a median age of 9 years (range 1-16)
  • Their child's risk of severe outcomes from COVID-19 due to underlying medical conditions e.g., obesity, medically fragile/medical complexities, more than one underlying medical condition, neurological disorders, Down Syndrome and other immuno-compromising conditions
  • Children who are infected with COVID-19 may also develop a post-COVID condition also known as long-COVID or post-acute COVID in which symptoms such as: brain fog/cognitive issues, breathlessness, fatigue, can continue for weeks or months. More information about Post-COVID-19 Care & Recovery can be found on the PHSA website.
  • Benefits of vaccination also include:
    • Reduced time away from school or activities, with positive impacts on physical and mental health of children as a whole 
    • Reduces their child's risk of becoming infected due to exposure to COVID-19 through in-person activities such as school, extra-curricular activities and in the community, realizing that this changes with time
  • The unknown risk of exposure to COVID-19 variants in the future should also be considered
  • Their child’s risk of transmitting COVID-19 to close contacts who themselves are at higher risk of severe outcomes due to older age or underlying medical conditions 2
 
 
No. COVID-19 vaccines do not cause infertility and there is no scientific reason to believe that they will cause infertility. Recent studies have shown that COVID-19 vaccines do not impact fertility.12, 13

The Society of Obstetricians and Gynaecologists of Canada (SOGC) addresses this online rumor in their recent statement stressing, “there is absolutely no evidence, and no theoretic reason to suspect that the COVID-19 vaccine could impair male or female fertility” and added, that “the widespread social media concern stems from misinformation about the similarities between syncytin-1 (used for placental implantation) and the SARS-CoV-2 spike protein. While the two proteins have several similar amino acids, they remain vastly different. The antibodies produced against the SARS-CoV-2 spike protein would not have cross-reactivity with syncitin-1.”14 
 

The dose of COVID-19 vaccine that a child receives is based on their age at presentation (see below).  An 11 year old child who received an age-appropriate dose of a COVID-19 mRNA vaccine (i.e., 10 mcg of the pediatric Pfizer-BioNTech vaccine or 50 mcg of the Moderna vaccine) who has turned 12 years of age when presenting for their second dose should receive the authorized dose for their age to complete their primary series (i.e., 30 mcg of the adult/adolescent Pfizer-BioNTech vaccine or 100 mcg of the Moderna vaccine). If the second dose is given as less than the authorized dose for the child's age (i.e., 10 mcg of the pediatric Pfizer-BioNTech vaccine or 50 mcg of the Moderna vaccine) the dose should still be consdered valid and the series complete. For more information refer to the Guidance Document on the Management of Inadvertent Vaccine Errors.




 
No. Children aged 5 to 11 are not required to show proof of vaccination.  

For more information go to the Proof of vaccination and the BC Vaccine Card page on the BC government website. 
1. BC Centre for Disease Control. COVID-19 situation report Week 10: March 6–March 12, 2022. Available from:  http://www.bccdc.ca/Health-Info-Site/Documents/COVID_sitrep/Week_10_2022_BC_COVID-19_Situation_Report.pdf

2. Statement from the Council of Chief Medical Officers of Health (CCMOH): COVID-19 Vaccination in Children 5-11 years of age. Available from: https://www.canada.ca/en/public-health/news/2021/11/statement-from-the-council-of-chief-medical-officers-of-health-ccmoh-covid-19-vaccination-in-children-5-11-years-of-age.html

3. National Advisory Committee o Immunization (NACI). November 2021. Recommendation on the use of the Pfizer-BioNTech COVID-19 vaccine (10 mcg) in children 5-11 years of age. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines/pfizer-biontech-10-mcg-children-5-11-years-age.html

4. New England Journal of Medicine. (November 9, 2021). Evaluation of the BNT162b2 COVID-19 Vaccine in Children 5 to 11 Years of Age. Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa2116298 

5. Oster, M. mRNA COVID-19 vaccine-associated myocarditis [slides presented at Advisory Committee on Immunization Practices (ACIP) meeting [Internet]. Atlanta (GA): Centers for Disease Control and Prevention (CDC); 2021 Nov 2 [cited 2021 Nov 10]. Available from: https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-11-2-3/04-COVID-Oster508.pdf.

6. Su JR. COVID-19 vaccine safety updates: Primary series in children and adolescents ages 5-11 and 12-15 years and booster doses in adolescents 16-24 years [Internet]. Atlanta (GA): CDC COVID-19 Vaccine Task Force; 2022 Jan 5 [cited 2022 Mar 24]. Available from: 

7. Brighton Collaboration. Myocarditis/pericarditis case definition [Internet]. Decatur (GA): The Task Force for Global Health; 2021 Jul 16. Available from: https://brightoncollaboration.us/myocarditis-case-definition-update/ 

8. Children’s Hospital of Philadelphia. (Nov. 11, 2021). Feature Article: 3 Considerations for COVID-19 Vaccination of 5-11 year old Children. Available from: https://www.chop.edu/news/feature-article-3-considerations-covid-19-vaccination-5-11-year-old-children 

9. Lazarus, R., Baos, S., Cappel-Porter, H., Carson-Stevens, A., et. al. (November 2021). Safety and immunogenicity of concomitant administration of COVID-19 vaccines (ChAdOx1 or BNT162b2) with seasonal influenza vaccines in adults in the UK (ComFluCOV): a multicentre, randomised, controlled, phase 4 trial. Available from: https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(21)02329-1.pdf 

10. Nilsson L, Csuth Á, Storsaeter J, Garvey LH, Jenmalm MC. Vaccine allergy: evidence to consider for COVID-19 vaccines. Curr Opin Allergy Clin Immunol. 2021 Aug 1;214:401,409. doi: 10.1097/ACI.0000000000000762.

11. Canadian Society of Allery and Clinical Immunology. (November 14, 2021). COVID-19 Vaccine Testing & Administration Guidance for Allergists/Immunologists from the CSACI. Available from: https://csaci.ca/wp-content/uploads/2021/11/2021-11-15-REVISED-UPDATE-COVID-19-Vaccine-Testing-Administration-Guidance_LBL.pdf

12. Bentov Y, Beharier O, Moav-Zafrir A, et al. Ovarian follicular function is not altered by sars-cov-2 infection or bnt162b2 mrna covid-19 vaccination. Hum Reprod. 2021. Available from: https://www.ncbi.nlm.nih.gov/pubmed/34364311 

13. Wang M, Yang Q, Ren X, et al. Investigating the impact of asymptomatic or mild sarscov-2 infection on female fertility and in vitro fertilization outcomes: A retrospective cohort study. EClinicalMedicine. 2021;38:101013. Available at https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00293-5/fulltext

14. Society of Obstetricians and Gynecologists of Canada. (March 2021). Statement on COVID-19 vaccination and fertility. Available from: https://sogc.org/common/Uploaded%20files/Latest%20News/EN_SOGCStatement_COVID-19Vaccination-Fertility.pdf 
 
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Non-replicating viral vector-based (adenovirus) COVID-19 vaccines

AstraZeneca, COVISHIELD and Janssen COVID-19 vaccines

Both AstraZeneca and COVISHIELD COVID-19 vaccines are viral vector-based vaccines that contain a modified version of a replication-deficient chimpanzee adenovirus (ChAdOx1). The Janssen COVID-19 vaccine is also a viral vector-based vaccine which uses a modified replication-deficient human adenovirus type 26 vector. These are different viruses than the one that causes COVID-19. These vaccines stimulate the body's natural defenses to protect against the SARS-CoV-2 virus. Inside the shell of the modified virus, there is material from the virus that causes COVID-19. This is called a “viral vector.” Once the viral vector has entered the cells involved in the immune response, the genetic material gives the cells instructions to make the COVID-19 spike protein, the same antigenic target to which immunity is generated by the mRNA vaccines. The protein is produced intracellularly and placed on the surface of the cell, generating both cellular and humoral (T-lymphocytes and B-lymphocytes) immunity.‎

 

Efficacy

AstraZeneca/COVISHIELD COVID-19 Vaccine

The estimated vaccine efficacy at least 15 days after Dose 2 in study participants who received the standard dose (SD) vaccine for both doses was 62.5% (95% CI: 50.7 to 71.4%), based on identification of 71/6,085 (1.2%) cases in vaccine recipients and 186/6,073 (3.1%) in controls. The estimated vaccine efficacy by age was 63.1% (51.1 to 72.1%) in study participants 18-64 years of age and 50.7% (-65.8 to 85.4%) in participants ≥ 65 years of age (NACI). It is important to note, however, that Phase 3 clinical trials of the AstraZeneca vaccine had a very small number of participants over 65 years of age that contracted COVID-19 to determine the efficacy of the vaccine in this age group.

 

Estimates of vaccine efficacy against hospitalization > 22 days after dose 1 was 100% (NACI). 

 

An exploratory analysis examined the potential effect of the interval between dose 1 and 2 on vaccine efficacy in study participants receiving the SD/SD vaccine regimen. This analysis indicated that efficacy was higher in those with a longer interval (> 12 weeks) at 81.3% (95% CI 60.3 to 91.2).1

 

A further exploratory analysis at > 22 days after the first dose found that a single standard dose vaccine provided protection against primary symptomatic COVID-19 in the first 90 days with an efficacy of 76.0% (95% CI 59.3 to 85.9), with no evidence of waning of protection during the same time period.2

 

Because this vaccine was not tested in head to head clinical trials against the mRNA vaccines, the results of the efficacy studies are not directly comparable. The vaccines were studied in different populations at different times. Both of the mRNA vaccines and ChAdOx1-S vaccine provide high levels of protection against severe COVID-19 disease.


Janssen COVID-19 Vaccine

The estimates of vaccine efficacy against confirmed symptomatic moderate to severe/critical COVID-19 infection with onsets ≥14 days and ≥28 days post-vaccination are 66.9% and 66.1%, respectively.

The estimates of vaccine efficacy against confirmed symptomatic severe/critical COVID-19 infection are 76.7% with onset ≥14 days post-vaccination and 85.4% with onset ≥28 days post-vaccination. The efficacy against confirmed symptomatic severe/critical COVID-19 infection with onset ≥14 days was calculated for four age groups: 18–59 (80.5%), 18–64 (78%), ≥60 (68.5%), ≥65 (69.9%). For confirmed symptomatic severe/critical COVID-19 infection with onset ≥28 days, the efficacy calculated for the same age groups was: 18–59 (91.7%), 18–64 (92.9%), ≥60 (70.3%), ≥65 (50.1%).3

1. Voysey M, Costa Clemens SA, Madhi SA, et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine  (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet [Internet]. 2021 Jan 9 [cited 2021 Mar 16];397(10269):99-111. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32661-1/fulltext

 

2. Voysey M, Costa Clemens SA, Madhi SA, et al. Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: A pooled analysis of four randomised trials. Lancet [Internet]. 2021 Mar 6 [cited 2021 Mar 16];397(10277):881-891. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00432-3/fulltext

 

3. Public Heath Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. 2021 May 3 [cited 2021 May 14]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines.html


Dosing, scheduling and administration

Refer to the BC Immunization Manual, Part 4 – Biological Products, COVID-19 vaccines for complete information on the viral vector-based COVID-19 vaccines prior to administration.

AstraZeneca and COVISHIELD COVID-19 vaccines are interchangeable within the vaccine series, however, these vaccines are no longer being offered as a first dose, unless there is a contraindication to the mRNA vaccines, or as advised by the Medical Health Officer or an allergist. 


On June 1, 2021, NACI recommended that individuals who received a first dose of the AstraZeneca/COVISHIELD vaccine may receive either AstraZeneca/COVISHIELD vaccine or an mRNA vaccine (Pfizer-BioNTech or Moderna) for their second dose unless contraindicated.


In the event that an individual receives one dose of the AstraZeneca/COVISHIELD vaccine and is unable to receive the same type of viral vector vaccine for the second dose, receiving the Janssen vaccine would be considered restarting a vaccine series, as one dose of the Janssen vaccine is considered to be a complete series.

 
Individuals receiving the AstraZeneca/COVISHIELD and Janssen vaccines should be reassured that adverse events are very rare, and COVID-19 infections can lead to significant complications, including a range of clotting disorders. Those who have been vaccinated with either product in the last month, should monitor for symptoms and seek immediate medical attention in the very unlikely event that they develop: 

  • Prolonged headache beginning 4 or more days after vaccination
  • Blurred vision
  • Difficulty speaking
  • Seizure
  • Difficulty moving parts of the body 
  • Shortness of breath
  • Chest pain
  • New severe swelling, pain or colour change of an arm or a leg
  • Persistent abdominal pain
  • Abnormal bruising, reddish or purple spots or blood blisters under the skin
  • Bleeding beyond site of vaccination 
It is important to note that although rare, the outcome of TTS can be serious including fatal. In addition to timely diagnosis and management, clinicians who identify vaccine recipients with TTS should promptly report such cases to the adverse events following immunization system in B.C.

In B.C., these vaccines are no longer being offered as a first dose, and individuals who have received 1 dose of AstraZeneca or COVISHIELD vaccine may receive either AstraZeneca/COVISHIELD vaccine or an mRNA vaccine (Pfizer-BioNTech or Moderna) for their second dose, unless contraindicated.

Contraindications and Precautions

The AstraZeneca/COVISHIELD and Janssen COVID-19 
vaccines are contraindicated in individuals with:
  • A history of anaphylactic reaction to a previous dose of the vaccine or to any component of the vaccine.
  • A history of thrombosis with thrombocytopenia following a previous dose of an adenovirus vector COVID-19 vaccine. These individuals should be offered an mRNA vaccine, pending a hematologist's recommendation.
  • A history of capillary leak syndrome.
For a list of components in the vaccine see Section 6 Dosage Forms, Strengths, Composition and Packaging of the respective viral vector-based vaccine product monographs found at:

 

The AstraZeneca/COVISHIELD and Janssen COVID-19 vaccines contain polysorbate 80 which can be found in various products such as cosmetics and medical preparations including vitamin oils, tablets, and anticancer agents.

In situations of suspected hypersensitivity or non-anaphylactic allergy to COVID-19 vaccine components, consultation with an allergist is advised. If there is a specific concern about a possible allergy to a component of the COVID-19 vaccine being administered, an extended period of observation post-vaccination of 30 minutes may be warranted; alternately, the vaccine can be administered in an emergency room setting, also with a prolonged observation period.‎

 
In late March, a safety signal emerged in several European countries of an unusual syndrome of acute venous or arterial thrombosis, new onset thrombocytopenia with or without hemorrhage with onset of symptoms by around 14 days after vaccination with AstraZeneca COVID-19 vaccine. Affected sites have included central venous sinuses, portal vein, splanchnic veins, and splenic veins. While the first case reports appeared largely in young to mid-adult age women, later updates indicated the occurrence of the event in both sexes, although with a preponderance of cases in females under 55 years old. Because denominator data on vaccine recipients have not been made available, accurate assessment of rates by age group and sex has been hampered. 

In early April the European Medicines Agency issued a warning about the occurrence of this syndrome, with information for both clinicians and recipients.1  Subsequently Health Canada also added a warning for both AstraZeneca COVID-19 vaccine and COVISHIELD.2  Some countries have not reintroduced the use of the vaccine since the recognition of these events, and others have advised against use below a certain age. While the Canadian National Advisory Committee on Immunization has issued updated recommendations, which currently allow for immunization of those aged 30 and older in moderately high and high COVID-19 incidence communities, following a benefit-risk assessment,these

vaccines are approved for individuals aged 18 years and older. 

This adverse event has been called Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT), Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) and more recently Thrombosis with Thrombocytopenia Syndrome (TTS) and is estimated to occur in approximately 1 in 50,000 vaccine recipients. The frequency of TTS following a second dose of AstraZeneca or COVISHIELD vaccine is currently reported as approximately 1 per 600,000. Epidemiological information about the syndrome is still evolving, and a similar syndrome identified in the United States appears to be associated with the Janssen (Johnson & Johnson) adenovirus vector vaccine.4 The biological mechanism is thought to be similar to that of spontaneous heparin-induced thrombocytopenia, as it occurs outside of the context of heparin treatment. The Ontario Science Table COVID-19 Advisory has issued diagnostic and treatment guidelines.5 The Updated Recommendation for AstraZeneca and COVISHIELD Vaccines letter dated March 29, 2021 provides recommendations for physicians whose patients received COVISHIELD/AstraZeneca COVID-19 vaccine.

While not a contraindication, individuals who have experienced cerebral venous sinus thrombosis (CVST) with thrombocytopenia, unrelated to adenovirus vector COVID-19 vaccination, or heparin induced thrombocytopenia (HIT), should only receive an adenovirus vector COVID-19 vaccine if the benefits outweigh the potential risks and an mRNA vaccine is unavailable.

 

Immune thrombocytopenia (ITP) is a bleeding disorder resulting in a decreased number of circulating platelets. Cases of immune thrombocytopenia with very low platelet levels (<20,000 per µL) have been reported to be very rare events following vaccination with either the AstraZeneca or Janssen COVID-19 vaccines (defined by the Canadian Immunization Guide as occurring at frequency of < 1 per 10,000 events). These include cases with bleeding and cases with a fatal outcome. Some cases have occurred in individuals with a history of immune thrombocytopenia. Symptoms can include spontaneous bleeding, bruising and petechiae with onset usually within the first four weeks after receiving vaccination. If an individual has a history of ITP, the risks of developing low platelet levels should be considered before vaccination, and platelet monitoring is recommended after vaccination.

 

Those vaccinated with a COVID-19 viral vector vaccine should be instructed to seek immediate medical attention if they develop symptoms such as shortness of breath, chest pain, leg pain or swelling, or progressive abdominal pain following vaccination. Additionally, anyone with neurological symptoms after vaccination including sudden onset of severe headaches, persistent or worsening headaches, blurred vision, confusion or seizure, or who experiences spontaneous bleeding, unusual skin bruising or petechiae beyond the site of vaccination after a few days, should seek prompt medical attention.

Venous thromboembolism (VTE) is a disorder that includes deep vein thrombosis and pulmonary embolism. Venous thromboembolism has been observed as a rare event following vaccination with the Janssen COVID-19 Vaccine (defined by the Canadian Immunization Guide as occurring at frequency of 1 per 10,000 cases to less than 1 per 1,000 cases). Those vaccinated should be instructed to seek immediate medical attention if they develop symptoms such as shortness of breath, chest pain, leg pain, leg swelling, or persistent abdominal pain following vaccination with Janssen COVID-19 vaccine. In individuals with a pre-existing increased risk for thromboembolism, the possible increased risk of VTE with vaccine use should be considered. 

 

1. European Medicines Agency. AstraZeneca's COVID-19 vaccine: EMA finds possible link to very rare cases of unusual blood clots with low blood platelets. April 7, 2021.

https://www.ema.europa.eu/en/news/astrazenecas-covid-19-vaccine-ema-finds-possible-link-very-rare-cases-unusual-blood-clots-low-blood

 

2. Health Canada. Recalls and Safety Alerts. Health Canada provides update on the AstraZeneca and COVISHIELD COVID-19 vaccines. Updated April 16, 2021. Accessed April 28, 2021. https://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2021/75389a-eng.php#:~:text=Healthcare%20professionals%20should%20tell%20people,headaches%20or%20blurred%20vision%3B%20or


3. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. 2021 April 23 [cited 2021 April 28]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci.html


4. Centers for Disease Control and Prevention. Atlanta GA. The Advisory Committee on Immunization Practices’ (ACIP) updated recommendations on the use of the Janssen (Johnson & Johnson) COVID-19 vaccine. Accessed April 24, 2021. Available from: https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html 


5. Pai M, Grill A, Ivers N, et al. Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) Following AstraZeneca COVID-19 Vaccination. March 26, 2021. https://covid19-sciencetable.ca/sciencebrief/vaccine-induced-prothrombotic-immune-thrombocytopenia-vipit-following-astrazeneca-covid-19-vaccination/

Vaccine storage and handling

‎The viral vector vaccines should be stored refrigerated at temperatures of +2°C to +8°C, similar to other routine non-COVID-19 vaccines in BC. Information regarding the storage and handling of refrigerated vaccines can be found in the BC Immunization Manual, Appendix E – Management of Biologicals.  


Additional information, including standard operating procedures (SOPs) can be found on the COVID-19 Immunize BC Operations Centre: Standard Operating Procedures page.

Additional information

The AstraZeneca/COVISHIELD and Janssen vaccines are manufactured using human embryonic cells for the propagation of the virus that contains the genetic information for the SARS-CoV-2 spike protein. The AstraZeneca/COVISHIELD vaccine uses the kidney cell line HEK-293 that was isolated in the 1970s while the Janssen vaccine uses the retinal cell line PER.C6 that was isolated in 1985. The cell lines are used widely in academic research and in the pharmaceutical and biotechnology industries. 

Although these cell lines are used in the manufacturing process, the final vaccine does not contain any cells.

The Catholic Church has stated that receiving a COVID-19 vaccine that required fetal cell lines for production or manufacture is morally acceptable.

‎The Serum Institute of India (SII) was founded in 1966 and is the world’s largest vaccine manufacturer. It produces more than 1.5 billion doses of vaccines each year. Vaccines from SII are used in national immunization programs in approximately 170 countries around the world. The vaccines used in these programs include diphtheria, tetanus, pertussis, Haemophilus influenzae type b, hepatitis B, measles, mumps and rubella. The SII is accredited by the World Health Organization and its facilities are compliant with good manufacturing practice (cGMP); this ensures that the vaccines manufactured by the SII are safe for use, contain the specified ingredients and have the required potency. 

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COVID-19 protein subunit vaccine (Novavax)

Refer to the BC Immunization Manual, Part 4 – Biological Products, COVID-19 vaccines for complete information on the COVID-19 protein subunit vaccine (Nuvaxovid™, Novavax) prior to administration.

While the National Advisory Committee on Immunization (NACI) continues to preferentially recommend the use of COVID-19 mRNA vaccines, they support the use of Novavax COVID-19 vaccine in Canada for those who have not yet received a primary series or booster dose and are not able (e.g., due to a contraindication or inaccessibility) or willing to receive an mRNA vaccine.

The authorization of the Novavax COVID-19 vaccine can help remove barriers to vaccination for people who want a protein-based vaccine or who are not willing or able to receive mRNA vaccines or viral vector vaccines. 

Having more authorized COVID-19 vaccines that meet Health Canada’s stringent safety, efficacy and quality requirements provides provinces and territories with an additional vaccine option to consider in their vaccination programs. In addition, Novavax COVID-19 vaccine storage and handling requirements are less complex than the COVID-19 mRNA vaccines as they are stored at refrigerator temperatures of +2°C to +8°C. 
The Novavax COVID-19 vaccine is a recombinant protein subunit vaccine. While this type of vaccine technology has been used for other vaccines such as the hepatitis B vaccine, this is the first COVID-19 vaccine authorized in Canada which uses this technology. 

Protein subunit vaccines are created by inserting a small piece of the virus’s genetic code into another cell (Novavax uses the Spodoptera frugiperda insect cell line) which instructs the cell to start building the virus spike protein from the original (Wuhan) strain. The virus spike protein is then extracted from the cell, purified and used as the active ingredient in the vaccine to stimulate an immune response. The Novavax COVID-19 vaccine includes a new type of adjuvant, Matrix-M, which helps the vaccine produce a better immune response.
The use of mRNA COVID-19 vaccines continues to be preferentially recommended due to the excellent protection they provide against severe illness and their well-known safety profile.
  
NACI supports the use of the Novavax COVID-19 vaccine for adults 18 years of age and older who are not able or not willing to receive an mRNA COVID-19 vaccine. The minimum age for vaccine receipt is based on age at presentation (i.e., the vaccine may be offered to individuals on or after their 18th birthday).
The Novavax COVID-19 vaccine was evaluated in two pivotal Phase 3 trials: 2019nCoV-301 conducted in the United States and Mexico and 2019nCoV-302 conducted in the United Kingdom.1   

In clinical trial 2019nCoV-301, the estimated vaccine efficacy at least 7 days after Dose 2 was 90.4% (95% CI: 82.9 to 94.6%), with 14 confirmed COVID-19 cases identified among vaccine recipients (n=17,312) compared to 63 cases among placebo recipients (n=8,140). All cases identified in the vaccine group were mild.

In clinical trial 2019nCoV-302, the estimated vaccine efficacy after a median follow-up after Dose 2 of 54 and 56 days in the placebo and vaccine groups, respectively, was 89.7% (95% CI: 80.2 to 94.6%), with 10 confirmed COVID-19 cases among the vaccine recipients (n=7,020) compared to 96 cases in the placebo group (n=7,019).

The duration of protection is not yet known. There is currently no data on the efficacy or effectiveness of the vaccine against the Delta or Omicron variants as clinical trials were conducted before the emergence of those variants.1
Cellular immune responses specific to the SARS-CoV-2 spike protein were elicited 7 days after the first dose and increased 7 days after the second dose.1, 2 The Novavax COVID-19 vaccine induces both binding and neutralizing antibodies against the SARS-CoV-2 spike protein. While both the binding and neutralizing antibodies were seen after one dose, the maximal immune responses were seen 14 days after the second dose, on day 35. Antibodies were detectable up to day 189, with neutralizing antibodies declining more rapidly compared to binding antibodies.1

In clinical trials, binding and neutralizing antibody titres were slightly lower in older participants (≥65 years of age) compared to younger participants (18 to <65 years of age) after 2 doses.1
 
There is emerging evidence that longer intervals between the first and second doses of COVID-19 vaccines result in more robust and durable immune responses and higher vaccine effectiveness. 
Evidence on mRNA COVID-19 vaccines in adult populations indicates that a longer dose interval such as 8 weeks, compared with the authorized 21-day interval, improves the immune response and is associated with greater vaccine effectiveness that may last longer. A similar observation was also seen with longer intervals for the AstraZeneca COVID-19 vaccine. This is consistent with general principles of vaccinology, and expected to also apply to recombinant protein subunit COVID-19 vaccines.

Longer intervals between vaccine doses leading to better immune response is based on two immunological concepts: affinity maturation and decreased immune interference. With affinity maturation, more time between vaccine doses allows for optimal B cell maturation, so that when the immune system encounters the vaccine again it produces better binding antibodies that may be more robust and broad. These types of antibodies may result in better protection on exposure to the same or different variants of the virus.3  Immune interference may occur when a second dose of vaccine is introduced into the body when there is still a high level of circulating antibodies, these antibodies may mask binding sites on the vaccine antigen preventing a good response to the vaccine. Allowing time for circulating antibodies to decrease between doses will help prevent immune interference and optimize responses to vaccines.3
 

Although a booster dose of a COVID-19 mRNA vaccine is recommended for individuals 18 years of age and older at least 6 months after the primary series has been completed, NACI recommends that a 0.5 mL booster dose of the Novavax COVID-19 vaccine may be provided as a booster dose to people who are unable or unwilling to receive an mRNA COVID-19 vaccine, regardless of which COVID-19 vaccines were received in the primary series. 

 

Yes, Novavax COVID-19 vaccine may be used in a heterologous (mixed) primary series or as a booster dose in a heterologous prime-boost (booster dose differs from the COVID-19 vaccine product(s) used in the primary series) for whom mRNA COVID-19 vaccine is contraindicated, inaccessible or has been refused.  To complete their primary series, people may receive two doses of Novavax COVID-19 vaccine (homologous primary series) or one dose of Novavax COVID-19 vaccine and one dose of another COVID-19 vaccine (heterologous primary series).

 
Novavax COVID-19 vaccine is contraindicated for individuals with a history of anaphylactic reaction to a previous dose of the vaccine or to any component of the vaccine. These individuals should be offered an mRNA COVID-19 vaccine and observed for at least 30 minutes after immunization. 

The Novavax COVID-19 vaccine contains polysorbate 80 which is considered a potential allergen. Polysorbate 80 can be found in various products such as cosmetics and medical preparations including vitamin oils, tablets, and anticancer agents. 

For a complete list of components in the vaccine see page 5 of the Novavax Nuvaxovid™ Product Monograph.
 

In clinical trials, myocarditis was identified in two teenage males shortly after receiving a second dose of the Novavax COVID-19 vaccine resulting in a mild clinical course with complete resolution and no sequelae. The biological mechanisms of action that could explain the association of myocarditis and/or pericarditis occurring after receipt of a COVID-19 vaccine are still under investigation and the information currently available is insufficient to determine a causal relationship with the vaccine. Post-market safety surveillance is required to determine whether this is an adverse event of interest associated with Novavax COVID-19 vaccine.1 

 

Novavax COVID-19 vaccine should be stored refrigerated at +2°C to +8°C up to the end of its expiry date. As this vaccine does not contain preservatives, once a vial has been punctured, the vaccine is to be stored at +2°C to 25°C and must be used within 6 hours. In addition, the vaccine can be pre-drawn into a syringe for up to 6 hours and stored at +2°C to 25°C. If the vaccine has not been used within this time it must be discarded.  Once opened, label the vaccine vial with the date and time of first vial puncture. More information on storage and handling requirements can be found in the BC Immunization Manual, Part 4 – COVID-19 Vaccines, NUVAXOVID™.

Yes. Novavax is accepted by the Government of Canada for the purpose of travel to and within Canada. To be considered fully vaccinated, travelers must have 2 doses of a Government of Canada-approved vaccine, at least 14 days prior to travel to Canada. More information about COVID-19 vaccination and travel can be found on the Government of Canada COVID-19: Travel, testing and borders website at the following link: https://travel.gc.ca/travel-covid/travel-restrictions/covid-vaccinated-travellers-entering-canada.

1. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Summary of National Advisory Committee on Immunization (NACI) statement: Recommendations on the use of Novavax Nuvaxovid COVID-19 vaccine. 2022 Feb 17 [cited 2022 Mar 11]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-novavax-nuvaxovid-covid-19-vaccine.html 

2. Keech C, Albert G, Cho I, Robertson A, Reed P, Neal S, et al. Phase 1-2 Trial of a SARS-CoV-2 Recombinant Spike Protein Nanoparticle Vaccine. N Engl J Med. 2020 Dec 10;383(24):2320,2332. Available from: https://www.nejm.org/doi/10.1056/NEJMoa2026920 
 
3. Public Health Agency of Canada. Vaccine Confidence InfoBulletin. 2022 Jan. [cited 2022 Mar 15]. Issue 9.
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Special considerations

The following are recommendations for COVID-19 immunization in some specific populations who were either excluded from, or were represented by small numbers of participants in clinical trials. The recommendations for these groups are evolving, and more data have become available in the future about both protection from the vaccine and its safety. 

More information on COVID-19 considerations in these populations can be found under clinically extremely vulnerable individuals on the COVID-19 vaccination toolkit for health professionals page.

Pregnant and lactating people 

Althought the safety and efficacy of the COVID-19 vaccines were not studied in people who are pregnant or breastfeeding in the clinical trials for these vaccines, evidence during the post-marketing period has evolved. Outcomes in participants who became pregnant during the clinical trials and fetal outcomes are reported through registries, and real-world evidence (mostly with mRNA vaccination) has become available. While a cautionary approach has been taken historically to immunization during pregnancy and lactation, accumulating data on safety of immunization with a variety of vaccines during pregnancy and breastfeeding over several decades has led to expanded recommendations for use of vaccines in pregnancy. Both NACI1 and the Society of Obstetricians and Gynaecologists of Canada (SOGC)2 have pre-existing general recommendations that inactivated viral vaccines can be safely given in pregnancy. The SOGC recommends that pregnant people, those contemplating pregnancy, and those who are breastfeeding who are at high risk of infection and/or morbidity from COVID-19 should be offered the vaccine.3 New data have become available from postmarketing surveillance without safety concerns being identified. This includes a recently published US study of 35,691 women who self-enrolled into a safety surveillance program and 221 women who reported adverse events through the passive surveillance system.4  

Both NACI and SOGC recommend that the pregnant or lactating person be informed about the evidence on the safety of mRNA COVID-19 vaccines in these populations. This information should include the findings that in some studies, pregnant individuals with COVID-19 infection are at higher risk of invasive ventilation compared to non-pregnant age-matched individuals. Severe morbidity in pregnancy is associated with similar risk factors to those seen in non-pregnant people, including older age, asthma, obesity, diabetes, hypertension and heart disease. Emerging evidence suggests that COVID-19 mRNA vaccination during pregnancy is immunogenic and results in comparable anntibody titres to those generated in non-pregnant women. Regarding theoretical risks of vaccine receipt, the COVID-19 vaccines are not live virus vaccines, and there is not a basis to consider that these would be harmful neither to the fetus nor to the breastfed infant. A small number of pregnant women were inadvertently enrolled in the phase 3 clinical trials and are being followed to the end of their pregnancy to assess outcomes. 


Immunocompromised 

Individuals who are immunosuppressed due to disease or treatment were not included in the initial COVID-19 vaccine clinical trials and as such there are limited data in these populations.5  Individuals who are immunosuppressed due to disease or treatment may have been observed to have a diminished immune response to the vaccine.

A primary series of three doses of an approved mRNA COVID-19 vaccine should be offered to individuals in the approved age group. For individuals who previously received a 1- or 2-dose complete COVID-19 series, an additional dose should be offered. In B.C., Moderna COVID-19 vaccine is preferentially recommended for all doses in the series. 

People living with stable HIV that are considered immunocompetent may receive the COVID-19 vaccine.5

Autoimmune disorders

Although participants with autoimmune conditions who were not immunosuppressed were not excluded from clinical trials of the vaccines, these constituted a very small proportion of trial participants and represent a very narrow range of autoimmune conditions. Specific conclusions about efficacy and safety, including risk of exacerbation of the condition, were not assessed. This theoretical risk of exacerbation was based on previous studies of mRNA vaccines designed for treatment of cancer and ability of the mRNA vaccines to elicit inflammation. The current mRNA COVID-19 vaccines have been optimized to reduce this risk.5

The Canadian Rheumatology Association recommends that on balance, a complete COVID-19 vaccine series should be offered to individuals otherwise eligible to receive the vaccine without additional barriers such as an individualized risk assessment or documented approval to proceed with immunization from their health care provider, with the exception of individuals on treatment with rituximab. Treatment with rituximab is expected to decrease effectiveness of the vaccine because of B-cell suppression. Such individuals should be off treatment for 5 months or longer prior to vaccination, and after vaccination, should not restart rituximab for at least 4 weeks in order to allow for adequate response to the vaccine. While other drug therapies for autoimmune disorders may reduce the immune response to the vaccine, most recipients will derive benefit from vaccination.6  

Individuals with autoimmune rheumatic diseases presenting for COVID-19 immunization who wish to proceed with vaccination, other than those treated with rituximab, should be offered immunization without referral to their health care provider. Those who are uncertain and wish to seek further advice can be referred to a decision aid developed by the Canadian Rheumatology Association with input from the Canadian Arthritis Patient Alliance. Alternately, they may prefer to have this discussion with their health care provider most familiar with their disease and treatment. 

NACI continues to recommend that COVID-19 vaccines should be offered to people who have previously been infected with SARS-CoV-2.  Vaccination continues to be very important, even for those with a prior SARS-CoV-2 infection, as vaccination will provide more reliable protection than a COVID-19 infection, and reduces the risk of experiencing severe outcomes. While infection alone may provide some protection, COVID-19 vaccination following infection strengthens the immune response and provides longer-lasting protection against COVID-19. While there is currently a lack of evidence on advantageous intervals between SARS-CoV-2 infection and COVID-19 immunization, NACI has developed interim guidance based on immunological principles, expert opinion and available evidence related to vaccine safety, immunogenicity, and vaccine effectiveness. Therefore, with the goal of improving long-term protection, NACI recommends that:

  • Individuals who have a recent positive COVID-19 test result (PCR or rapid antigen test) before starting or completing their primary COVID-19 vaccine series may receive the vaccine 8 weeks after symptoms started or after testing positive (if no symptoms were experienced).
  • Individuals who are recommended to receive a booster dose that have a recent positive COVID-19 test result (PCR or rapid antigen test) may receive a booster dose 3 months after their symptoms started or after testing positive (if no symptoms were experienced) provided it is at least 6 months after completing the primary series.
The longer intervals between infection and vaccination, as noted above, may result in a better immune response and longer-lasting protection against Omicron and future variants, and the likelihood of reinfection during these periods of time is small. However, risk factors for exposure and severe outcomes should be assessed when considering longer intervals. Individuals who wish to be vaccinated sooner can receive an initial or subsequent dose of COVID-19 vaccine following SARS-CoV-2 infection as soon as their symptoms have resolved and they are no longer required to self-isolate. 

Yes. General immunization guidelines support coadministration of other indicated vaccines at the same visit, at a different injection site(s). This includes both inactivated and live vaccines, if the individual is behind schedule or due to receive these vaccines, and if these are not contraindicated in their circumstances. If not given at the same visit, these vaccines can be given before or after the COVID-19 vaccine, without regard to the number of days or weeks of this interval.


While formal studies of coadministration have not been conducted yet, general guidelines on immunization are to use every visit as an opportunity to offer recommended vaccines.

There are currently no data to inform whether COVID-19 vaccines affect TST or IGRA results. However, current knowledge about the immunologic response to COVID-19 vaccination is that it does not appear to impact TST or IGRA results. At the outset of the COVID-19 vaccination programs, there was a theoretical concern that COVID-19 vaccines may temporarily affect cell-mediated immunity, resulting in false-negative TST or IGRA test results.7

However, in cases where an opportunity to perform the TST or IGRA test might be missed, the testing should not be delayed since these are theoretical considerations. Therefore, TST and IGRA tests can be administered and read without regard to COVID-19 immunization. Re-testing (at least 4 weeks post immunization) of individuals with negative results for whom there is high suspicion of TB infection may be prudent in order to avoid missing cases due to potentially false-negative results.5
If administration of the second dose of a COVID-19 vaccine is delayed, the second dose should be provided as soon as possible, and the series does not need to be restarted. In general, regardless of the time between doses, interruption of a vaccine series does not require restarting the series as delays between doses do not result in a reduction in final antibody concentrations for most other vaccines requiring more than one dose for a series. Maximum protection may not be attained until the complete vaccine series has been administered.

In BC, while vaccine supplies were limited, the time between first and second dose was extended to up to 4 months. This allowed a greater number of people to receive the important protection from a first dose of vaccine, given limited vaccine supply currently and high rates of COVID-19 transmission. The Canadian National Advisory Committee on Immunization (NACI) supported the delay of the second dose up to 4 months.8  

As of May 27, 2021, the recommended interval between dose 1 and dose 2 for the mRNA vaccines (Pfizer-BioNTech or Moderna) is 8 weeks. The recommended interval between dose 1 and 2 of the viral vector-based vaccines (AstraZeneca or COVISHIELD) is 8 to 12 weeks.

More information on the evidence and the decision to defer the second dose of COVID-19 vaccine in BC can be found in the Public health statement on deferral of second dose COVID-19 vaccine in BC.

Prophylactic oral analgesics or antipyretics (e.g., acetaminophen or non-steroidal anti-inflammatory drugs such as ibuprofen) should not be routinely used before or at the time of vaccination. While these medications may be used after vaccination (see below), it is not known whether these may blunt the antibody response to vaccine. This phenomenon has been observed in some studies of other vaccines in children, although its clinical significance is unknown.9, 10, 11 If an individual has taken one of these medications prior to immunization for any reason, they should be immunized as planned.  

 

Oral analgesics or antipyretics may be considered for the management of symptoms attributed to the vaccine (e.g., pain, fever, headache, myalgia) if these cannot be readily tolerated using non-pharmaceutical strategies.   

 
Lymphadenopathy (reactive adenopathy related to the immune response generated by the vaccine) in the regional nodes draining the deltoid area can occur. Such enlarged nodes may be viewed in imaging studies such as mammograms, and may be interpreted as abnormal and indicative of potential pathology. Some radiologists have recommended that routine imaging examinations including screening mammograms be scheduled before or at least 6 weeks after the vaccine dose in order to avoid misinterpretation of findings. 

The BC Cancer Agency recommends that scheduled screening mammograms should not be cancelled because of COVID-19 immunization. Those undertaking imaging within 6 weeks following vaccination should be asked for information about the site of vaccination so that this information can be recorded and considered in the interpretation of the radiograph. For those scheduling their appointments in conjunction with recent receipt or future scheduling of COVID-19 vaccine, this information should be provided to the booking clerk so that the screening appointment can be made before vaccination or 6 weeks after vaccination.12

Individuals for whom there are clinical indications (such as identification of a new breast mass or short-interval treatment monitoring or management of complications) for imaging should not delay imaging because of recent vaccination. 

For those being vaccinated in the context of suspect or known breast malignancy, the vaccine should be given in the contralateral arm for both doses.  
There have been increasing reports that some clients are requesting injection with aspiration. These requests are likely due to two recent studies in mice that seem to establish the possible link between small chances of vaccine leakage into the bloodstream and either rare instances of myocarditis or thrombosis with thrombocytopenia syndrome (TTS).     

As indicated in the BC Immunization Manual, Appendix B: Administration of Biological Products, aspiration prior to injection of a vaccine is no longer recommended as there are no large blood vessels at the recommended immunization sites and aspiration can increase pain resulting from the combined effects of a longer needle-dwelling time in the tissues and shearing action (wiggling) of the needle. Aspiration was originally recommended for theoretical safety reasons, however the veins and arteries within reach of a needle in the anatomic areas recommended for vaccination are too small to allow an intravenous push of vaccine without blowing out the vessel.

While there is no evidence to support the need for aspiration, there is no prohibition on aspiration when administering a vaccine. Therefore, to avoid barriers and missed opportunities for COVID-19 immunization, this procedure could be done to accommodate case-by-case requests. However, clients should be informed of the possibility of increased pain and discomfort at the injection site. Providing the rationale for not aspirating with injection may assist the client in making an informed choice on the procedure which may include the following information: 
  • There is no scientific evidence to support the need for aspiration 
  • There are no published reports of adverse effects associated with not aspirating 
  • The deltoid site used for intramuscular injection is not in close proximity to large blood vessels, therefore the possibility of inadvertently hitting a blood vessel is rare
  • For aspiration to be effective, it must be sustained for at least 5-10 seconds 
  • Injection with aspiration is more painful, likely because aspiration, when performed correctly for 5-10 seconds, results in longer contact time between the needle and the tissue and movement of the needle within the tissue during aspiration is expected
  • Bleeding at the injection site is common, and does not indicate incorrect injection technique or injection into a blood vessel
 
Needle aspiration is performed by pulling back on the plunger (applying negative pressure) of the syringe after inserting the needle into the client and prior to injecting the vaccine and includes the following steps:
  • After the needle pierces the skin, use the thumb and forefinger of the non dominant hand to hold the syringe barrel
  • Move the dominant hand to the end of the plunger 
  • Avoid moving the syringe 
  • Aspirate by holding the barrel of the syringe steady with your non dominant hand and by pulling back on the plunger with your dominant hand 
Effective aspiration may require 5 to 10 seconds prior to injection; if blood appears in the barrel of the syringe during this time, do not inject the vaccine and withdraw the needle, and properly discard the syringe. 


1. National Advisory Committee on Immunization. Canadian Immunization Guide [Internet]. Evergreen ed. Ottawa (ON): Public Health Agency of Canada; 2012 [updated 2020 Dec 24]. Part 3 - Immunization in pregnancy and breastfeeding; [cited 2021 Jan10]. Available from: https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-3-vaccination-specific-populations/page-4-immunization-pregnancy-breastfeeding.html

 

2. The Society of Obstetricians and Gynaecologists of Canada [Internet]. Ottawa (ON): The Society of Obstetricians and Gynaecologists of Canada. SOGC statement on COVID-19 vaccination in pregnancy. 2021 Jan 11 [cited 2021 Jan 13]. Available from: https://sogc.org/common/Uploaded%20files/Covid%20Information/SOGC_Statement_COVID-19_Vaccination_in_Pregnancy.pdf

 

3. Castillo E and Poliquin V. Immunization in pregnancy. J Obstet Gynaecol Can [Internet]. 2018 Apr [cited 2021 Jan 10];40(4):478-89. Available from:  https://www.jogc.com/pb/assets/raw/Health%20Advance/journals/jogc/JOGC-672.pdf

 

4. Shimabukuro TT, Kim SY, Myers TR, Moro PL, Oduyebo T, Panagiotakopoulos L, Marquez PL, Olson CK, Liu R, Chang KT, Ellington SR, Burkel VK, Smoots AN, Green CJ, Licata C, Zhang BC, Alimchandani M, Mba-Jonas A, Martin SW, Gee JM, Meaney-Delman DM; CDC v-safe COVID-19 Pregnancy Registry Team. Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons. N Engl J Med. 2021 Apr 21. doi: 10.1056/NEJMoa2104983. Epub ahead of print. PMID: 33882218.

5. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. 2021 April 23 [cited 2021 April 28]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci.html


6. Canadian Rheumatology Association. Recommendations on COVID-19 vaccination in persons with autoimmune rheumatic disease. January 2021. https://rheum.ca/wp-content/uploads/2021/11/V3_Nov_23_2021_EN.pdf

 

7. Centers for Disease Control and Prevention [Internet]. Atlanta (GA): U.S. Department of Health & Human Services.  Interim clinical considerations for use of mRNA COVID-19 vaccines currently authorized in the United States; [updated 2021 Jan 6; cited 2021 Jan 8]. Available from:  https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html

 

8. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. NACI rapid response: Extended dose intervals for COVID-19 vaccines to optimize early vaccine rollout and population protection in Canada. 2021 Mar 8 [cited 2021 Mar 16]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/rapid-response-extended-dose-intervals-covid-19-vaccines-early-rollout-population-protection.html

 

9. Saleh E, Moody MA, Walter EB. Effect of antipyretic analgesics on immune responses to vaccination. Hum Vaccin Immunother [internet]. 2016 Sep 1 [cited 2021 Jan 10];12(9):2391-402. Available from: https://www-tandfonline-com.ezproxy.library.ubc.ca/doi/full/10.1080/21645515.2016.1183077 

 

10. Chau-Giendinning H, Baber B, Neher JO, Safranek S. Do prophylactic antipyretics reduce vaccination-associcated symptoms in children? J Fam Pract [Internet]. 2020 Apr [cited 2021 Jan 10];69(3):E21-22. Available from: https://cdn.mdedge.com/files/s3fs-public/JFP06904e21.pdf

 

11. Das RR, Panigrahi I, Naik SS. The effect of prophylactic antipyretic administration on post-vaccination adverse reactions and antibody response in children: a systematic review. PLoS One [Internet]. 2014 Sep 2 [cited 2021 Jan 10];9(9):e106629. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0106629

 

12. BC Cancer. COVID-19 and Cancer Screening. Does the COVID-19 vaccine affect my screening mammogram? Accessed April 28, 2021. http://www.bccancer.bc.ca/screening/health-professionals/covid-19-and-cancer-screening

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Individuals who are immunocompromised

NACI strongly recommends that moderately to severely immunocompromised individuals in the authorized age group be vaccinated as follows:

Those who have not received a complete COVID-19 vaccine series:
  • Should be immunized with a primary series of three doses of mRNA vaccine.
  • The Moderna vaccine is recommended for all doses in the series because it may produce a greater immune response in this population.1
Those who previously received a complete primary COVID-19 vaccine series (including one dose of Janssen vaccine, or a mixed series of mRNA/viral vector vaccines):
  • Should receive an additional dose of mRNA vaccine. 
In B.C., the Moderna COVID-19 vaccine is preferentially recommended for all doses in the series.

In a meta-analysis of 22 studies (refer to the NACI statement and references therein) assessing seroconversion after the initial 2-dose series in immunocompromised and dialysis populations, Pfizer-BioNTech had slightly lower pooled rates of seroconversion than Moderna with relative risk of 0.94 (95% CI = 0.91 to 0.97) with moderate heterogeneity between studies (I2 = 65%, χ2 = 59.6, p˂0.0001).2 As such, Moderna vaccine is preferentially recommended for the third dose, which should be provided at least 28 days after the second dose. However if Moderna is unavailable, Pfizer-BioNTech should be given.
 
To date, people with moderately to severely compromised immune systems have been observed to generally have lower antibody responses and lower vaccine effectiveness from a complete 2-dose vaccine series (1-dose if vaccinated with Janssen vaccine) than immunocompetent individuals, although this varies depending on the underlying condition or immunosuppressive agents. 

Although the evidence is limited, observational studies show a reduction in vaccine effectiveness against SARS-CoV-2 infection and disease in immunocompromised adults when compared to the general population. A pooled analysis of three large population-based cohort studies 3, 4, 5 estimated vaccine effectiveness against any SARS-CoV-2 infection after the second dose in immunocompromised persons to be 79% (95% confidence interval (CI): 69-91%), compared to vaccine effectiveness after the second dose in the general population of 90% (95% CI: 86-95%).

The impact of immunocompromise on seroconversion after vaccination varies according to specific conditions and/or immunosuppressive therapy. Not all immunocompromised populations have been studied in detail. 

In addition, breakthrough infections (infection in fully vaccinated people) have occurred. This may be due to some degree of evasion of vaccine-induced immunity or waning of vaccine-induced immunity over time, or poor immune response to initial vaccine doses (as might occur amongst those who are moderately or severely immunocompromised). In order to reduce the risk of breakthrough infections among vulnerable groups several countries including Israel, the United States, France, Germany, the United Kingdom, Denmark and Norway have implemented, or are planning to implement, the administration of third doses of COVID-19 vaccine in some immunocompromised populations.
 

The additional dose of COVID-19 vaccine should be provided at least 28 days after the completion of the 2-dose series (1-dose if vaccinated with Janssen vaccine). Although studies on immunogenicity have shown that an interval longer than the minimum 28 days between doses is likely to result in a better immune response, use of an interval longer than 28 days should be considered against the risk of exposure to SARS-CoV-2 due to current epidemiology, variants of concern and the risk for severe disease. Some immunocompromised individuals may still be susceptible after the 2-dose primary series, so their period of susceptibility until receipt of the additional dose will also increase if the interval between doses is increased.

Third dose eligibility in B.C. is inclusive of all of the groups suggested for a third dose by NACI. The one major difference is that in B.C. we have made the decision to make patients who are on dialysis and/or with severe kidney/renal disease to be eligible for a third dose. This decision is based on rapidly growing literature that some patients undergoing hemodialysis had a poor antibody response to vaccinations (JAMA Network Open. 2021;4(9):e2123622. doi:10.1001/jamanetworkopen.2021.23622). 

We are also seeing within our BC data that dialysis patients who have completed a two dose COVID-19 vaccine series are being infected with COVID-19, indicating that their immune response may be insufficient. Other provinces, such as Quebec and Ontario, have been offering third doses to dialysis patients. 

Radiation therapy is commonly used for patients with solid or haematological malignancies. Radiation therapy can suppress lymphocyte counts for months to years after treatment in a dose and volume dependent fashion. After consultation with BC Cancer's radiation oncologists, it was decided that people who are undergoing radiation therapy would be eligible for a third dose to ensure that they develop a sufficient immune response.
There will be additional recommendations in the coming weeks for select groups of people who are immunocompromised.

The clinically extremely vulnerable (CEV) originally prioritized for COVID-19 vaccination included those people who would be more at risk of serious illness or hospitalization if they got COVID-19. However, many of the people in this group do mount a good immune response to the vaccine and are protected. 

Data now supports that a group of severely immunocompromised people whose immune response to a two-dose series is likely to be blunted, or not respond at all, should be offered a third dose to increase their chances of having a protective immune response with their initial vaccine series. 

Within the CEV group, there are people whose conditions made them at risk of serious illness if they got COVID-19 but whose condition does not prevent them from getting good protection through a good immune response from the two vaccine doses. People with these conditions do not require an additional dose. The evidence of vaccine effectiveness is reviewed closely for all CEV subgroups and the general population. If the evidence changes over time that will be considered in B.C.’s provincial vaccine strategy moving forward. 
 

Since the appearance of the Omicron variant, infection rates have markedly increased among Canadian children reaching record-high levels since the start of the pandemic.6 Although the risk of severe outcomes remains low for this age group, children 5-11 years of age with immunocompromising conditions are at increased risk.B.C. guidelines have aligned with NACI and recommend that children 5 years of age and older with the eligible conditions that make them moderately to severely immunocompromised receive a third dose of vaccine for their primary series. Clinical trials of COVID-19 vaccines for younger children (i.e., those 6 months to 4 years of age) are still being conducted. 

 
In ten studies in adults, (five in solid organ transplant patients, three in patients on dialysis, one in patients with non-hematologic cancer and one in patients with hematologic cancer), the reactogenicity of a third dose of COVID-19 vaccine was similar to that of prior doses. In nearly all studies, the third dose was an mRNA vaccine, with the exception of one study where Janssen was also used for some study participations as an additional dose following a 2-dose mRNA COVID-19 vaccine primary series. However, there are no data specific to the Janssen COVID-19 vaccine when used as an additional dose in this population. No worsening of underlying disease was reported after immunization, however a few cases of graft versus host disease or organ rejection were reported. Without unvaccinated controls however, it is not possible at this time to determine if receipt of a third COVID-19 vaccine dose could potentially be associated with an increased risk of rejection in this population. No serious adverse events were deemed to be associated with the vaccine. Limitations of these studies include small sample sizes, short follow up periods and heterogeneous populations/vaccine schedules. Due to the small size of these studies and limited follow-up times, the impact of additional doses on rare adverse events in these populations are unknown.

The risk of myocarditis and/or pericarditis following receipt of an mRNA COVID-19 vaccine is currently reported more commonly after second doses compared to first doses. The risk of myocarditis and/or pericarditis associated with an additional dose of an mRNA vaccine, including when given to immunocompromised individuals, is unknown at this time. NACI is continuing to monitor the evidence and will update recommendations as information becomes available.
 

The additional or third dose recommended for moderately to severely immunocompromised persons should be distinguished from that of a booster dose. The intent of a booster dose is to restore protection that may have waned over time in individuals who responded adequately to an initial 1- or 2-dose primary vaccine series. Additional doses beyond the standard primary vaccine series, such as being recommended for those moderately to severely immunocompromised, provide an opportunity for individuals who may not have achieved an adequate level of protection from the standard primary vaccine series to develop a better immune response.

 
1. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Canadian Immunization Guide: COVID-19 Chapter. 2022 January 14 [cited 2022 February 8] Available from: https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-26-covid-19-vaccine.html


2. Moayyedi P, Fernandes A, Yuan C, Farbod Y, Pittayanon R, Kanno T. The effects of vaccination in immunocompromised people. Rapid review of research studies on immunogenicity, safety, and efficacy/effectiveness of COVID-19 vaccines in immunocompromised individuals (unpublished draft). Toronto (ON): SPOR Evidence Alliance; 2021 Aug 25


3. Barda N, Dagan N, Balicer RD. BNT162b2 mRNA Covid-19 Vaccine in a nationwide mass vaccination setting. Reply. N Engl J Med. 2021 May 20;384(20):1970. doi: 10.1056/NEJMc2104281.


4. Chodick G, Tene L, Rotem RS, Patalon T, Gazit S, Ben-Tov A, et al. The effectiveness of the TWO-DOSE BNT162b2 vaccine: analysis of real-world data. Clin Infect Dis. 2021 May 17:ciab438. doi: 10.1093/cid/ciab438.


5. Whitaker HJ, Tsang RSM, Byford R, Andrews NJ, Sherlock J, Pillai PS, et al. Pfizer-BioNTech and Oxford AstraZeneca COVID-19 vaccine effectiveness and immune response among individuals in clinical risk groups. Preprint posted on khub. 2021 Jul 9. https://khub.net/documents/135939561/430986542/RCGP+VE+riskgroups+paper.pdf/a6b54cd9-419d-9b63-e2bf-5dc796f5a91f.


6. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. NACI updated recommendations on the use of COVID-19 vaccines in children 5-11 years of age. 2022 January 25 [cited 2022 February 10] Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/updated-recommendations-use-covid-19-vaccines-children-5-11-years-age.html

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Allergic event following a dose of COVID-19 vaccine

As of November 26, 2021 a total of 59,999,590 COVID-19 vaccine doses have been administered in Canada. There have been 27,747 adverse event reports with 21,304 considered non-serious and 6,443 considered serious. Of the serious reports, 671 severe allergic reactions or anaphylaxis have been detected for all COVID-19 vaccines across Canada. More information about reported adverse events following COVID-19 vaccine can be found on Health Canada’s Reported side effects following COVID-19 vaccination in Canada page. 

In BC, from December 13, 2020 to November 27, 2021 there have been a total of 8,625,058 COVID-19 vaccine doses administered. There have been 4,666 adverse events reported following COVID-19 vaccination with 339 meeting serious definition. These included 13 individuals admitted to hospital for anaphylaxis. There have been 426 reports of events managed as anaphylaxis (i.e., the client received epinephrine for a suspected anaphylactic reaction). Of these, 234 (55%) met the Brighton Collaboration definition for anaphylaxis with diagnostic certainty leves of 1, 2 or 3. Upon further review of these reports, many may reflect events such as anxiety or pre-syncopal (fainting) events. Refer to the Brighton Collaboration Anaphylaxis: Case Definition Companion Guide and the Anaphylaxis: Case Definition Pictorial Algorithm for additional information. More information about B.C.’s reports on adverse events can be found on BCCDC’s Vaccine Safety page. 

Recent reports of reactions to COVID-19 vaccines have increased concerns about their safety for individuals with allergies. The Canadian Society of Allergy and Clinical Immunology (CSACI) guidelines stress that there is a low risk for allergic reactions to vaccines and non-allergic reactions to vaccines are more common than allergic reactions. In addition, non-allergic reactions to vaccines also include anxiety-related adverse events that can mimic allergic reactions.1 It is important to note that other, less serious reactions may mimic allergic reactions such as vasovagal syncope which are not contraindications to further vaccination.2 

Additional information regarding allergies and COVID-19 vaccine for the public can be found in the CSACI’s COVID-19 Vaccines FAQ resource.
 
It is important to first determine whether the allergic 
reaction was an anaphylactic reaction. If an individual experienced a serious adverse event following immunization (AEFI) an AEFI report may be available in the provincial immunization data system. The AEFI report will contain details about the AEFI as well as the Medical Health Officer (MHO) recommendation on further immunization. 

Although anaphylaxis occurs rarely after vaccination it is potentially life threatening and requires immediate treatment. It is characterized by sudden onset, rapid progression of signs and symptoms and is set apart from simple allergic reactions by the simultaneous involvement of several organ systems. Anaphylaxis that has been proven to be causally associated with vaccines is estimated at a frequency of 1.3 episodes per 1,000,000 doses of vaccines administered.3 Very rare cases of severe immediate reactions (e.g., anaphylaxis) following vaccination with COVID-19 vaccines have been reported in countries throughout the world with an incidence estimated between 2 to 7.9 cases per million doses administered.4 There have been no fatalities nor long-term morbidity described with these events.5  

The checklist below can be used as a tool to assist health care providers to determine how to proceed when an individual reports an allergic reaction following a COVID-19 vaccine.
  • Was the reported event an anaphylactic reaction to a previous dose or any component of COVID-19 vaccine? 
  • Was the event reported to public health as an AEFI?
  • If reported to public health, is an MHO recommendation available? 
  • Did the MHO recommend a COVID-19 vaccine from a different vaccine platform? E.g., recommendation to administer a COVID-19 mRNA vaccine for someone who had an anaphylactic reaction to a COVID-19 viral vector vaccine.
 
A potential allergen found in the COVID-19 mRNA vaccines (Pfizer-BioNTech and Moderna) is polyethylene glycol (PEG). 
  • Polyethylene glycol (PEG) can also be found in: cosmetics, skin care products, contact lens care solutions, cough syrup, laxatives, and bowel preparation products for colonoscopy. PEG is also used as an additive in some processed foods and drinks. However, no cases of anaphylaxis to PEG in foods and drinks have been reported.
A potential allergen found in the COVID-19 adenoviral vector vaccines (AstraZeneca/COVISHIELD and Janssen) is Polysorbate 80. 
  • Polysorbate 80 can also be found in cosmetics and medical preparations which may include: vitamin oils, tablets, and anticancer agents.
More information and full lists of the components present in each COVID-19 vaccine can be found in the BC Immunization Manual, Part 4 – Biological Products, COVID-19 vaccines.
 
 

‎Very rare cases of severe immediate allergic reactions (e.g., anaphylaxis) have been reported following immunization with COVID-19 mRNA vaccines. History of an anaphylactic reaction to any component of the vaccine is generally considered a contraindication. However, for individuals with a history of anaphylactic reaction to a previous dose of an mRNA COVID-19 vaccine, administration of a subsequent dose in the series may be offered with the same vaccine or the same mRNA platform if a risk assessment deems that the benefits outweigh the potential risks for the individual and if informed consent is provided.  NACI states, “the risk of a severe immediate allergic reaction after re-immunization appears to be low and no long-term morbidity has been associated with re-vaccination.”6  In addition, recent studies have shown that most of the individuals who had these reactions after a previous dose of mRNA vaccine can be safely re-vaccinated with the same vaccine or another mRNA COVID-19 vaccine.7,8,9,10 Prior to re-vaccination, the following steps are recommended:

  • Consultation with an allergist or other appropriate physician (e.g., medical health officer (MHO)) should be sought prior to re-vaccination.
  • If re-vaccinated, vaccine administration should be done in a controlled setting with expertise and equipment to manage anaphylaxis. Individuals should be observed for at least 30 minutes after re-vaccination. For example, a longer period of observation is warranted for individuals exhibiting any symptom suggestive of an evolving AEFI at the end of the 30 minute observation period.
Although such individuals may be offered a viral vector vaccine, re-vaccination with an mRNA vaccine is preferred due to the better effectiveness and immunogenicity of mRNA vaccines and the possible adverse effects specifically associated with viral vector vaccines (e.g., Thrombosis with Thrombocytopenia Syndrome [TTS]). 

If an adenoviral vector vaccine (e.g., AstraZeneca or Janssen) is recommended, the client should call 1-833-838-2323 and inform the agent that they have been recommended an adenoviral vector vaccine. Due to small supplies of these vaccines in the province, they will be added to a wait list for receipt of the respective vaccine. 

History of anaphylactic reaction to a previous dose of a COVID-19 viral vector vaccine or to any component of the vaccine is a contraindication to receiving a subsequent dose. These individuals should be offered a COVID-19 mRNA vaccine if a risk assessment deems that the benefits outweigh the potential risks for the individual and if informed consent is provided. If re-vaccinated, individuals should be observed for at least 30 minutes after re-vaccination. 

 

Any adverse event including an allergic reaction following a COVID-19 vaccine dose, should be reported to public health to be investigated by a medical health officer (MHO) or designate who will provide a recommendation on further vaccination. Adverse events following immunization (AEFI) reports and recommendations can be accessed from the provincial immunization data system. The individual who experienced an AEFI that was reported to public health will be notified of the MHO recommendations on further immunization. The MHO recommendations will also be sent to their most responsible health care provider. 


Any health professional who is aware of an adverse event following immunization must report the event to the medical health officer as per the Public Health Act. Information on AEFI reporting can be found on the BCCDC COVID-19 vaccination health care provider tool kit on the Adverse Events Following Immunization (AEFIs) page. More information about reporting anaphylaxis and other allergic reactions can be found in the BC Immunization Manual Part 5 - Adverse Events Following Immunization. In addition, the Report of Adverse Event Following Immunization with COVID-19 Vaccine is a one page form available that health care providers can use to report an AEFI with COVID-19 vaccines.

 

1. Vander Leek TK, Chan ES, Connors L et al. COVID-19 vaccine testing & administration guidance for allergists/immunologist from the Canadian Society of Allergy and Clinical Immunology (CSACI). Allergy Asthma Clin Immunol 17, 29 (2021).  https://doi.org/10.1186/s13223-021-00529-2


2. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. Appendix A. 2021 Jul 22 [cited 2021 Sep 23]. Available from:

https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines.html


3. Anaphylaxis and other Acute Reactions following Vaccination: Canadian Immunization Guide-Canada.ca [Internet]. 2020. Available from:

https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-2-vaccine-safety/page-4-early-vaccine-reactions-including-anaphylaxis.html                                                                                                                         
4. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Recommendations on the use of COVID-19 vaccines. [cited 2021 Dec 7]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines.html

5. Canadian Society of Allergy and Clinical Immunology [Internet]. Orleans (ON): Canadian Society of Allergy and Clinical Immunology. COVID-19 vaccine testing & administration guidance for allergists/immunologists from CSACI. 2021 November 14 [cited 2021 December 7]. Available from: https://csaci.ca/wp-content/uploads/2021/11/2021-11-15-UPDATE-COVID-19-Vaccine-Testing-Administration-Guidance.pdf
  
6. Public Health Agency of Canada [Internet]. Ottawa (ON): Public Health Agency of Canada. Summary of National Advisory Committee on Immunization (NACI) statement: Recommendations on the use of COVID-19 vaccines. 2021 Oct 22 [cited 2021 Dec 7]. Available from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-covid-19-vaccines/summary-october-22-2021.html 
 
7. Krantz MS, Kwah JH, Stone CA Jr, Phillips EJ, Ortega G, Banerji A, et al. Safety evaluation of the second dose of messenger RNA COVID-19 vaccines in patients with immediate reactions to the first dose. JAMA Intern Med. 2021 Jul 26. doi: 10.1001/jamainternmed.2021.3779. 
  
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