The Public Health Agency of Canada (PHAC) has officially ended a nationwide measles outbreak that resulted in more than 6,400 cases across 10 provinces and territories over two years. The agency announced the closure after more than two months passed without a new associated case, Medscape reported.
Canada lost its measles elimination status in November 2025
Canada first eliminated measles in 1998. For nearly 30 years, the country averaged between 0 and 752 cases annually, with a mean of 91. However, after the same virus strain showed sustained transmission for over a year, PHAC announced in November 2025 that the country had lost its elimination status.
Isaac Bogoch, MD, a professor of medicine at the University of Toronto and infectious diseases specialist at Toronto General Hospital, told Medscape that a high-income country with a sound healthcare system should not have been in a position to lose this status. He attributed the decline to a lack of funding and a lack of trust in public health initiatives.
Did you know?
Unvaccinated populations drove the 6,400-case surge
Data indicates that more than 90% of the cases during the two-year outbreak occurred among people who were unvaccinated or had an unknown vaccination status. A study published in The BMJ found that the outbreak was concentrated in historically under-vaccinated communities with close social networks spanning Canada, the U.S., and Mexico.
| Outbreak Metric | Figure / Impact |
|---|---|
| Total Cases (BMJ Study Cohort) | 2,377 |
| Unvaccinated Rate | 89% (2,121 individuals) |
| Hospitalizations | 166 admissions (13 to ICU) |
| Severe Outcomes | 1 encephalitis case, 1 infant death |
The multijurisdictional outbreak began in New Brunswick via a patient exposed outside Canada. According to The BMJ, 73% of the cases in their studied cohort occurred in individuals aged 19 or younger.
Clinics face risks from cross-border transmission
Despite the end of this specific outbreak, 1,126 measles cases had been reported in Canada as of October 26, 2024, according to the measles and rubella weekly monitoring report. This includes two cases in Quebec reported between October 11-17 that were unrelated to the main outbreak.
Herd immunity requires 95% vaccination rate
Matthew Muller, MD, PhD, medical director of infection prevention and control and an infectious diseases physician at St. Michael’s Hospital and Unity Health Toronto, told Medscape that achieving a 95% vaccination rate is necessary for herd immunity.
PHAC recommends that Canadians and healthcare professionals verify their status, noting that two doses of a measles-containing vaccine provide strong protection. The BMJ study concluded that culturally tailored community engagement is essential to rebuild trust and prevent future resurgences.
Common questions about Canada’s measles status
When did Canada lose its measles-free status?
PHAC announced the loss of elimination status in November 2025 after the virus showed sustained transmission for more than one year.
Who was most affected by the recent outbreak?
According to The BMJ, 73% of cases in their cohort were 19 years old or younger, and 89% of those cases were unvaccinated.
What is the recommended vaccination level to stop outbreaks?
Dr. Matthew Muller stated that 95% of the population must be vaccinated to achieve herd immunity and protect vulnerable individuals.
As of October 26, 2024, PHAC continues to monitor seven active measles cases across British Columbia, Ontario, and Quebec.
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