Information for healthcare providers about measles.
Measles is a highly infectious disease caused by the rubeola virus. Since the introduction and broad uptake of measles-containing vaccine, rates of measles infections have dropped greatly in Canada and around the world. However, measles is making a resurgence in British Columbia and across Canada as immunization rates decline and the number of travel-imported cases and local transmission increases. Updated information on measles cases in British Columbia can be found on the
BCCDC measles page and information on measles cases in Canada can be found on the
Public Health Agency of Canada website.
Canada achieved measles elimination status (absence of endemic virus transmission for 12 months) in 1998. However, given ongoing transmission of measles across the country, Canada is at-risk of losing its elimination status.
The incubation period for measles from exposure to onset of prodromal symptoms is between 7 to 18 days. The interval from exposure to rash onset averages 14 days but can appear as late as 21 days from exposure.
Measles is one of the most communicable infectious diseases with greater than a 90% attack rate among people who are susceptible. The measles virus spreads through the air when a person who is infected breathes, coughs, sneezes or talks. It may also spread through direct contact with fomites or secretions from the nose and throat of a person who is infected. The measles virus can persist in the air or on surfaces for up to 2 hours after a person who is infected has left the space.
Airborne precautions should be used for patients with confirmed or suspected measles. Additional resources on Infection Prevention and Control for measles can be found below:
People with confirmed measles are infectious for 1 day before the beginning of the prodromal period (usually about 4 days before rash onset) to 4 days after rash appearance in a healthy person and for the duration of measles illness in an immunocompromised person.
People with confirmed measles infection will be asked by public health to isolate for the duration of their infectious period. Susceptible (i.e., non-immune) contacts of measles cases may also be asked by public health to quarantine for up to 21 days after their last exposure to measles.
Common symptoms of measles include:
- Fever
- Cough
- Sore Throat
- Conjunctivitis
- Coryza
- Malaise
- A pathognomonic enanthema (white spots on the buccal mucosa called Koplik spots)
- A maculopapular erythematous rash that begins on the face and spreads to the trunk, arms, and legs which usually appears 14 days after infection and 3 to 7 days after prodromal symptoms begin
Courtesy of Dr. CW Leung, Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong.
Courtesy of the U.S. Centers for Disease Control and Prevention.
Courtesy of the U.S. Centers for Disease Control and Prevention.
These symptoms may be attenuated or not all present in patients who are immunocompromised or who have modified measles (i.e., measles in people who have previously been immunized and responded to the vaccine).
Common complications from measles include otitis media, pneumonia, and diarrhea. Severe complications include respiratory failure and encephalitis (1 in 1000 cases). Approximately 1 in 10 cases of measles are hospitalized and death is estimated to occur in 1 to 10 of every 10,000 cases in higher-income countries.
Measles is also known to cause immune amnesia for several years after infection, a condition where the virus erases the immune system’s memory and makes a person more prone to other infections.
Longer-term sequalae of measles includes blindness, deafness, permanent neurologic deficits, and subacute sclerosing panencephalitis (SSPE) – a rare and fatal degenerative central nervous system disease that can occur 7 to 10 years after initial infection.
Measles complications are more likely in people who are pregnant, people who are immunocompromised, and people less than 5 years of age. For example, measles in pregnancy can lead to maternal pneumonia, hepatitis, and death as well as increased rates of spontaneous abortion, fetal growth restriction, and preterm birth.
Measles diagnosis is made through a combination of clinical symptoms, epidemiologic linkage (e.g., known contact with a measles case or living/traveling to an area where measles is spreading), and laboratory testing. PCR (NP/Throat/Urine) is generally preferred, although serologic testing is indicated in certain situations.
There is no specific antiviral treatment for measles infection. Medical management is supportive and aimed at symptom relief and management of complications. This can include rehydration and management of secondary complications of measles, such as bacterial pneumonia.
Additional resources for measles in children & youth and pregnancy can be found below:
Immunization is the best way to prevent measles and is very effective in preventing disease. Measles vaccination is given as a two-dose series, with one dose being 85-95% effective and two doses approaching 100% effectiveness in preventing measles.
In British Columbia, children are routinely provided with two doses of a measles-containing vaccine:
Note: Earlier administration of these vaccines (e.g., 6-11 months for first dose, under 4 years of age for second dose) is generally not recommended unless someone is traveling to an area where measles is spreading within Canada or abroad.
Adverse events from the measles-containing vaccine are typically mild and usually resolve without medical intervention. Reactions can include local reactions like pain, redness, and swelling at the injection site. Other side effects can develop 1 to 3 weeks following vaccination and can include a rash which is usually mild, and/or a fever. Serious adverse events following vaccination are very rare.
As measles-containing vaccines are live attenuated vaccines, they are generally contraindicated in people who are immunocompromised and in people who are pregnant.
People are considered immune (protected) against measles if they:
- Have two doses of measles-containing vaccine or
- Were born before 1970 (1957 for healthcare workers) –immunity presumed due to measles infection (as the disease was circulating widely during this time) or from immunization; or
- Have laboratory evidence of immunity (e.g., positive measles serology) or
- Have had a prior measles infection.
Note: Serologic testing for routine assessment of measles immunity is NOT recommended. If people are unsure of their immunization history, the best approach is to offer them another measles-containing vaccine.
Post-exposure prophylaxis (PEP) can be offered to susceptible contacts of measles cases to prevent infection in some circumstances. PEP is either given in the form of MMR vaccine (if within 3 days of exposure and not contraindicated) or as immune globulin – IMIG or IVIG (if within 6 days of exposure). Generally speaking, immune globulin may be recommended for:
- Susceptible infants 0-12 months of age
- Susceptible pregnant women and people
- People with certain immunocompromising conditions
If someone is potentially eligible for PEP, please contact public health within your region as soon as possible for assessment of PEP.
