Canada’s chief public health officer Theresa Tam Theresa Tam told The Globe and Mail in an interview this week that if measles cases extend beyond October, the country will lose its measles elimination status and the virus will be considered endemic.Adrian Wyld/The Canadian Press
The country’s chief public health officer says the spread of measles could continue for a year and she is urging all Canadians to make sure their vaccinations are up to date.
Theresa Tam, whose term will come to an end next month, told The Globe and Mail in an interview this week that if cases extend beyond October, the country will lose its measles elimination status and the virus will be considered endemic. This means the virus will continue to circulate domestically.
“What that means is children are at risk,” Dr. Tam said, adding what unfolds here is not simply a risk to Canada. “We will be responsible for exporting measles to others as well.”
A recent risk assessment from the Public Health Agency of Canada said the likelihood of prolonged transmission of measles in the next six months is moderate to high and Canada is in jeopardy of losing the elimination status earned in 1998, owing to the measles, mumps, rubella (MMR) vaccine.
Measles elimination is achieved when transmission is interrupted for 12 consecutive months or more.
“Uninterrupted transmission from current outbreaks places Canada at risk of losing measles elimination status if vaccination efforts and non-pharmaceutical public health measures are unable to interrupt transmission,” the assessment said.
Canada has seen multiple jurisdictions with cases of the highly contagious virus this year, but the situation is particularly concerning in the country’s most populous province.
In its weekly surveillance report released on Thursday, Public Health Ontario said there were 182 new cases in the last week. Since last October, there is a total of 1,622 measles cases (1,389 confirmed, 233 probable) associated with an outbreak in more than a dozen public-health units.
Alberta has the second-highest case count, with 374 cases reported, including 61 new cases this week.
Dr. Tam said Canada must redouble efforts to stop the spread of the virus. The response needs to involve not only public-health officials but Canadians too, she said.
“Everyone has a role in my mind,” she said. “For individuals, check on your vaccination status and get updated and ask questions if you have them.”
Schools and families can play a role to ensure children are vaccinated, she said, adding individuals should be aware of the global resurgence of measles if they are travelling internationally and to ensure they are immunized.
Other countries are also grappling with the spread of measles, and Dr. Tam said Canada must work with others as part of a global effort.
Lower immunization rates are currently an issue. Dr. Tam said overall immunization is not high enough and needs to be boosted, or the country will be vulnerable to the introduction of measles cases and its spread. She added that 95-per-cent coverage is required because the virus is so infectious. The MMR vaccine is considered to be a safe and effective tool to protect against the virus.
The chief public health officer said there are communities where vaccination coverage is really low, and measles spreads fast when it gets into an undervaccinated community. She did not specify which communities are particularly vulnerable.
In a January statement, Dr. Tam pointed to research showing childhood immunizations are on the decline. A study published in the Canadian Journal of Public Health found a decline in measles vaccination coverage in children in 2023 compared with 2019.
Public-health officials have attributed this decline to school-based immunization programs being put on pause during the COVID-19 pandemic, challenges for many Canadians to see primary care providers who have traditionally been responsible for administering childhood immunizations, along with vaccine hesitancy and the rise of misinformation.
In a 2024 report on the state of public health, Dr. Tam said vaccination has become a polarized topic, particularly across digital and social-media platforms.
Misinformation and disinformation have grown in scale and have become more sophisticated, she said, adding the speed and reach online pose a public-health threat.
