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Monitoring vaccine uptake, safety and effectiveness

Learn more about how B.C. will monitor vaccine uptake, safety and effectiveness.

Last updated: April 8, 2021


COVID-19 immunization will be carefully documented. B.C. will closely monitor vaccine safety, uptake and effectiveness.

You can find the latest information on how many COVID-19 vaccine doses have been administered in B.C. on the British Columbia COVID-19 Dashboard. Refer to the “Vaccine Information” tab on the bottom to see number of doses administered and number of doses distributed.

Ongoing monitoring of vaccine safety

Once a vaccine is approved and begins to be used, vaccine safety is continuously monitored to identify any serious adverse events.  If these events happen, authorities investigate to identify whether the vaccine is directly responsible for the adverse effect. If required, a vaccine can be withdrawn from the market and not used.

Adverse events following immunization are reported to the Public Health Agency of Canada and global safety surveillance systems. 

Vaccine providers should refer to this one-page resource on reporting adverse events following immunization

Vaccine safety surveillance is conducted for all vaccines including the COVID-19 vaccines under a regulatory framework in BC. This report summarizes the reports of COVID-19 vaccine adverse events following immunization (AEFI). 


No unusual or concerning signals have been identified in B.C. or in Canada. 


Use of AstraZeneca and COVISHIELD vaccines in people under 55 years of age

Earlier this month, some European countries stopped using the AstraZeneca vaccine while looking into a small number of reports of serious blood clots after vaccination. An analysis by the European Medicines Agency (EMA)  concluded that the vaccine was not associated with an increase in the overall risk of blood clotting events. However, it acknowledged there may be a very rare risk of abnormal bleeding and clotting including a particular type of stroke.

Read more about the changes to the use of AstraZeneca and COVISHIELD vaccines 
These events are called vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) and have happened primarily among women under the age of 55. There has been fewer than 30 cases identified around the world, primarily in Europe.

Overall, these blood clotting events are very rare, occurring in 1 to 10 in 1 million vaccine recipients, and none of these events have been reported in B.C. or Canada following vaccination. However, Health Canada and provincial health systems continue to monitor adverse events very closely.

B.C. and the National Advisory Committee on Immunization (NACI) recommend that the AstraZeneca and COVISHIELD vaccines be used in people over the age of 55 for the time being. B.C. has paused the use of these vaccines in younger populations until more information is available.

This change in recommendation shows how B.C. and Canada's vaccine safety monitoring system works. Officials continuously monitor safety reports and adverse events in Canada and around the worldHealth Canada can take immediate action and withdraw a vaccine if there is concern of harm. It can also issue warnings about specific risks in order to inform individuals.  

If you have already received a COVISHIELD vaccine and have questions about the signs and symptoms of VIPIT, please refer to Vaccination Aftercare

Vaccine effectiveness

All vaccines approved in Canada and available in B.C. are safe and effective and will help protect you against COVID-19. In clinical trials, those who had received a vaccine were significantly less likely to become sick with COVID-19.  While some people may still get COVID-19 after they have been vaccinated, all vaccines have been shown to have a high level of protection against serious illness and death. 

Early research findings on the COVID-19 vaccine in British Columbia show that a single dose of the mRNA vaccine reduced the risk of COVID-19 in long-term care residents and health care workers by 80 per cent within two to three weeks after vaccination. 

Vaccines begin to work a couple of weeks after vaccination. The first people to be vaccinated in B.C. were long term care residents and health care workers. The research shows that within two to three weeks of receiving their first dose of vaccine, there was a pronounced drop in the number of cases among vaccinated individuals and a reduction in hospitalizations and deaths among vaccinated long term care residents.

The findings are comparable to vaccine effectiveness results released by Quebec and Israel. Together, the studies reinforce the substantial protection afforded by a single dose of COVID-19 vaccine. 

Learn more about the clinical trial and real world results of vaccine effectiveness following the first dose of vaccine.

Vaccination and immunity

COVID-19 is a relatively new disease. We are still learning how our immune systems respond to it. We are also learning how long immunity lasts after getting COVID-19 or getting immunized.

The initial data for some of the leading vaccines has been encouraging. We are hopeful the vaccines will provide safe and effective protection against COVID-19. This would reduce severe illness in those who get sick.

After immunizations begin, it continues to be important to wash your hands, physically distance, wear a mask, and stay home when sick. These methods of protection are still essential as vaccines roll out.

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