While most of Canada's current measles case have been linked to international travel, some in Quebec and one in Ontario have not, meaning the virus is being transmitted in communities.Eric Risberg/The Associated Press
The discovery of measles cases in several provinces is prompting public health officials to recommend Canadians check their vaccination status before travelling abroad.
Ten cases of measles have been confirmed in the Greater Montreal area over the past few weeks, while five cases have been reported in Ontario, and at least one in both B.C. and Saskatchewan.
While most of the cases have been linked to international travel, some in Quebec and one in Ontario have not, meaning the virus is being transmitted in communities.
The measles virus is airborne and highly communicable, with symptoms that at first mimic those of a cold or flu: fever, cough, runny nose and red, watery eyes. Around two to three days after symptoms begin, small white spots may appear inside the mouth and throat. Around three to seven days later, a rash develops on the face and spreads down the body, arms and legs. The incubation period is around 10 days, and those infected are contagious from four days prior to a rash appearing and four days after.
The virus can lead to serious complications, including pneumonia and respiratory failure. According to the Public Health Agency of Canada. about one in 1,000 people infected with measles will develop encephalitis, or brain inflammation, which can cause deafness, blindness and development disability in children.
One to three out of every 1,000 people with measles will die as a result of the disease.
Canada’s Chief Public Health Officer, Theresa Tam, has strongly advised Canadians to get vaccinated with two doses of the measles vaccine, especially before travelling. In 1998, measles was declared eliminated in Canada, meaning cases were no longer originating in this country. But this year, more than a dozen cases have been reported. In 2023, only 12 cases were reported for the entire year.
Preventing the spread of measles within a community requires 95 per cent of the population to be vaccinated. But measles vaccination coverage has dropped below that mark in the country, partly because of the disruption to routine childhood immunizations during the COVID-19 pandemic, Canada’s public health agency said.
Here’s what to know about checking your vaccine history and where to get a dose if needed.
How many doses of the vaccine should people get?
Both measles, mumps and rubella (MMR) and measles, mumps, rubella and varicella (MMRV) vaccines are available. The efficacy of a single dose given at 12 or 15 months of age is estimated to be 85 to 95 per cent. With a second dose, it’s nearly 100 per cent effective.
Unlike COVID-19 or the flu, the measles virus is stable and does not mutate. This means that people who had two doses as a child are still immune today, and people who have recovered from measles have permanent immunity.
Infants
Babies are one of the highest risk groups for measles and aren’t eligible for the vaccine until their first birthday. But infants who are six months to 11 months can get a dose of the MMR vaccine if they are travelling to an area with measles spread. Public health experts say caregivers should speak to a health professional to determine eligibility.
Children
Two doses of the vaccine are recommended for routine childhood immunization. The first dose of either MMR or MMRV vaccine should be administered at 12 to 15 months of age, and the second dose at 18 months of age or any time before starting school (around four to six years old).
If a child or adolescent who is younger than 18 years old misses the routine vaccinations, they should receive two doses of the vaccine, administered at least four weeks apart.
Adults born after 1970
Adults born in or after 1970 who have not previously had measles or been vaccinated are recommended to get two doses. People who are pregnant should not get the MMR or MMRV vaccines because of the theoretical risk to the fetus.
Adults born before 1970
These adults can be presumed to have acquired natural immunity to measles because they likely were infected while the disease was endemic in Canada. If you know you did not have measles or have not been immunized and are travelling internationally, you can get one dose of the vaccine. The World Health Organization issued an alert in December about what it described as an “alarming” rise in measles cases in Europe.
Adults with greater risk of exposure
All adults who are at a greater risk of measles exposure – such as health care workers and military personnel – are recommended to get two doses of the MMR vaccines.
For more information, the government of Canada has a full breakdown of immunity criteria.
How to check your or your child’s vaccination records:
To obtain your vaccination records, contact your family doctor or any previous primary health care providers. You can also contact your local public health authority.
Where can I get a vaccine?
You can get the MMR or MMRV vaccine from your family doctor, provincial public health units or offices, and some pharmacies, depending on the province. Pharmacies in British Columbia, New Brunswick and Newfoundland currently offer the measles vaccine for adults and children four years and older.
I can’t find my vaccine records. What now?
Canada’s public health agency says that if you don’t remember whether you received a second dose, or if there’s any doubt, talk to a health care provider about getting a booster shot.
There is no harm in getting another dose of MMR vaccine even if it turns out you did have two shots, said Shelly Bolotin, director of the Centre for Vaccine Preventable Diseases at the University of Toronto’s Dalla Lana School of Public Health. “There’s no relationship between adverse events and more doses that you have. It’s a very, very, very safe vaccine.”
More reading:
André Picard: The return of measles is cause for concern – not disdain
Dr. Dawn Bowdish: Measles is not some harmless childhood infection
With reports from Carly Weeks, Frédérik-Xavier Duhamel and The Canadian Press
Editor’s note: This article has been updated to clarify that adults born in or after 1970 who have not previously had measles or been vaccinated are recommended to get two doses of the vaccine.