A dose of the measles, mumps, and rubella vaccine at Southwestern Public Health in St. Thomas, Ont., in March, 2025.Geoff Robins/The Canadian Press
Six months after Canada was stripped of its measles elimination status, public health officials are still struggling to get the outbreak under control, particularly as cases surge in Manitoba.
Canada officially lost its long-held measles elimination designation last November after failing to interrupt transmission of the highly contagious virus within one year of its outbreak. The country had held on to this status for nearly three decades prior.
The first locally acquired case of measles was recorded on Oct. 27, 2024, in New Brunswick, before quickly spreading to other provinces. Alberta and Ontario were hardest hit but Manitoba is now the province with the highest caseload, totalling more than 600 so far this year.
Natasha Crowcroft, deputy chief public health officer with the Public Health Agency of Canada (PHAC), said efforts to stifle the spread of measles were set back by the Manitoba insurgence but the main driver of transmission in Canada is low vaccination rates.
“The reason the outbreak is continuing to carry on is because there are still enough unimmunized people in the affected communities,” said Dr. Crowcroft. “It’s a bit like how wildfires can actually carry on over winter if there are still roots to burn under the snow.”
Manitoba outpacing other provinces in measles cases
It will eventually burn out, she said, but health officials don’t know how long that will take.
Ontario managed to declare its provincial measles outbreak over last October, just shy of its one-year mark. National guidance states an outbreak is over when no new cases have been reported for 46 consecutive days.
In Alberta, transmission has slowed but cases continue to trickle in, with roughly 300 reported this year. About 2,000 were recorded in 2025 but Alberta does not report probable cases, meaning the total is likely much higher.
Manitoba is now leading the pack after significant exposures at large-scale events, including an agricultural showcase in January and a Winnipeg Jets game in early February.
Dr. Crowcroft said, for how small Manitoba’s population is, the outbreak is “quite significant.” She said some cases have spread from Manitoba to other provinces, including Ontario and British Columbia.
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“We weren’t anticipating what happened in Manitoba, but that’s the game we’re in. Infectious diseases, viruses, jump on every opportunity to survive,” she said.
“We’re watching it and hoping that this sort of little uptick will settle down. We’ve also been working our way through the peak transmission season for measles as well, so as we get into the summer, it should also dampen down.”
A handful of cases have also been reported this year in Nova Scotia, Quebec and Saskatchewan, according to national data. While most cases in Canada are linked to the 2024 outbreak, there are other strains circulating.
When Canada lost its designation, PHAC said it would work with provincial and territorial partners to bring the situation under control with a focus on strengthening vaccine coverage, surveillance and data sharing.
Dr. Crowcroft said there has been increased demand for the measles, mumps and rubella vaccine, or MMR, across Canada over the past six months but that no province or territory has reached the coverage rate of 95 per cent needed for herd immunity.
As of Dec. 31, 2024, 80.4 per cent of two-year-olds were adequately vaccinated against measles. Immunization guidelines in Canada recommend the first MMR dose between 12 to 15 months of age and second dose at 18 months or older.
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“We’ve got work to do to get coverage up,” said Dr. Crowcroft, noting that access to immunization services can be a challenge in parts of country, particularly in rural and remote communities where health services are limited.
On improving surveillance, she said Ottawa is on the verge of completing a public health sharing agreement with all provinces and territories that should bolster national data.
The domestic return of measles has been especially present in Mennonite communities across Canada, where vaccine hesitancy and opposition has opened the door for the virus to jump from host to host with limited hurdles. Building trust in these communities is critical to improving vaccine coverage.
The same is true in the United States and Mexico, which are experiencing outbreaks of the same genotype that has spread in Canada and are also at risk of losing their elimination status. The Pan American Health Organization (PAHO), a regional arm of the World Health Organization, will review the status of both countries in November.
Canada can earn back its designation if it records one continuous year without sustained measles transmission.
Jarbas Barbosa, director of PAHO, said it is obvious Canada is committed to stamping out measles, but said it is a difficult virus to put back in the box considering it is one of the most contagious in the world.
Even so, Dr. Barbosa said: “I’m very optimistic that Canada will be able to stop the transmission.”