Measles is making a troubling comeback in Canada this year, with cases rising sharply after years of near-elimination.
So far this year, Canada has reported 95 cases of measles (as of Feb. 21), with British Columbia, Manitoba, Ontario and Quebec bearing the brunt of the outbreak, the latest data from the Public Health Agency of Canada (PHAC) shows.
At this time last year, there were only four reported measles cases.
By the end of 2024, Canada had recorded a total of 146 cases.
“If you look at Ontario in the 2025 calendar year, it’s only February. And we already have roughly the same amount of cases of measles in February of 2025 as we did all of 2024. So no, we are not headed in the right direction,” said Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital.
Measles is one of the most contagious infectious diseases — more contagious than diseases like COVID-19, influenza and chickenpox. This high level of contagiousness is one reason why measles outbreaks can spread rapidly, particularly in areas with low vaccination rates.
“It’s so transmissible; if someone was in a room that had the measles and then they left the room, and an hour or two later, another person entered that room who is not immune to measles, there’s a high probability that they would get infected with measles,” Bogoch said.
“It has a knack for finding unvaccinated or under-vaccinated people and under-vaccinated communities.”
The measles virus spreads easily through the air when an infected person breathes, coughs, sneezes or even talks. It can also spread by touching surfaces or objects that have been contaminated with the virus, according to PHAC.
Complications from measles can be serious, including pneumonia, brain swelling, permanent hearing loss and even death, especially in young children or those with weakened immune systems.
Dr. Theresa Tam, chief public health officer of PHAC, warned that measles is a serious illness, with about one in five infected children requiring hospitalization.
“Many parents haven’t had the experience of seeing measles,” she told Global News.
“When children get measles, they’re miserable. They have a high fever, red eyes, they feel really unwell. And then the classic rash that starts on your face and moving down into the body… it is not a trivial illness.”
The latest data from PHAC shows that between Feb. 2 and Feb. 8, 34 new measles cases were reported in Manitoba, Ontario and Quebec. Additionally, Ontario reported three new probable cases linked to an ongoing outbreak.
Two measles cases have also been reported in British Columbia, both involving residents who recently travelled to Southeast Asia. Health authorities are warning that members of the public may have been exposed to the virus via an Air Canada flight on Feb. 11.
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The data also reveals that 78 per cent of those infected were unvaccinated.
The majority of reported cases were among individuals aged five to 17 (45 per cent), followed by those aged 18 to 54 (26 per cent) and children aged one to four (17 per cent).
One of the main factors behind the spike in measles cases in Canada, Bogoch explained, is the significant global resurgence of the virus.
This global rise in measles cases has led to importations of the virus into Canada, resulting in outbreaks, particularly in regions with pockets of unvaccinated individuals.
“There’s a ton of this circulating around the world. We’re also living in the most mobile time in human history, where people can travel all over the world, and we know that there’s going to be inevitable cases of measles landing in Canada,” Bogoch said.
Whether people have missed their measles doses, haven’t caught up, face barriers to access or are influenced by misinformation, vaccine rates for measles are declining, Bogoch said.
A study published in October 2024 in the Canadian Journal of Public Health found that vaccination rates for the measles, mumps and rubella (MMR) vaccine declined in 2023 compared with 2019, before the pandemic. Specifically, coverage for one dose of MMR dropped from 89.5 per cent to 82.5 per cent.
The most significant declines occurred during 2020 and 2021, and the drop in vaccination rates has continued since the pandemic, according to the authors.
This reduction has left an increasing number of people vulnerable to infection, weakening community immunity. To effectively prevent measles outbreaks and maintain herd immunity, at least 95 per cent of the population must be vaccinated.
“Our results show a decline in routine vaccination coverage was observed during the COVID-19 pandemic in Canada,” the authors stated.
“The pandemic and its associated vaccination campaign were accompanied by a large spread of misinformation, not only about COVID-19 vaccines, but about vaccines in general.”
The disease was declared eradicated in Canada in 1998 following an extensive immunization campaign.
However, in recent years, it has resurfaced due to a decline in vaccination rates, according to Health Canada. Most cases come from abroad, brought into the country by travellers who are not vaccinated or who are under-immunized.
Because the measles virus can spread before symptoms appear and remain contagious for an extended period, outbreaks are difficult to contain once they begin.
This highlights the importance of vaccines, experts like Bogoch state.
“Cases should be preventable. We have a very effective vaccine, it’s extraordinarily safe. It has decades of data for safety and efficacy. And like everything on the planet, nothing’s 100 per cent perfect, but it is still a very, very effective vaccine,” he emphasized.
The risk of measles spreading is heightened where there are a lot of unvaccinated or non-immune people clustered together in regions or communities.
And while measles vaccination rates are high in Canada, Health Canada said they are still below “the necessary threshold for community immunity in some places.”
The measles vaccine is available in Canada as measles-mumps-rubella (MMR) or measles-mumps-rubella-varicella (MMRV) vaccine.
The first dose of a measles-containing vaccine is usually given to children at 12 months of age. The second dose is usually given at 18 months of age or between four and six years of age.
Since its approval in Canada in 1963, the vaccine has led to a decrease of more than 99 per cent in measles cases, according to the federal government.
The efficacy of a single dose of the measles vaccine given at 12 or 15 months of age is estimated to be between 85 and 95 per cent. PHAC states that with a second dose, efficacy is nearly 100 per cent.
