Most measles cases in Canada stem from domestic outbreaks: federal government

A dose of the measles, mumps, and rubella vaccination awaits the next patient at a vaccine clinic at Southwestern Public Health in St. Thomas, Ont. on March 4, 2025. (Geoff Robins / The Canadian Press)

Most people who have caught measles this year in Canada were exposed to the virus in the country, according to the latest federal government data. It comes amid the country’s biggest measles surge in 27 years.

“Canada is currently experiencing increased measles activity,” Public Health Agency of Canada spokesperson Anna Maddison wrote in an email to CTVNews.ca this week. “Most cases in 2025 have been exposed to the virus in Canada as part of domestic outbreaks.”

So far this year, 2,935 individuals were exposed to measles in Canada compared to 45 who were exposed outside the country, according to the federal government’s latest measles and rubella report as of the first week of June. Meanwhile, the exposure source was “unknown” or “pending” for 190 cases.

For the Canadian cases, Maddison said people were exposed to the highly contagious virus in airports, airplanes, trains, sporting events and other public settings.

• What’s the risk of catching measles at airports? Here’s what travellers need to know

An outbreak that began in New Brunswick last October has spread throughout the country, affecting 2,248 people in total as of June 7, including 2,161 just this year and accounting for most of the cases so far in 2025.

This outbreak is the largest in the country since 1998, with recent cases in Ontario, Manitoba and British Columbia. New Brunswick’s outbreak was declared over in January, according to the government.

Cases are at a 27-year high in Canada with more than 3,100 reported so far this year compared to only 17 for all of 1998. One death was reported in Ontario this year.

Measles has been “eliminated” in the country since 1998, meaning any new cases are imported from other countries but these cases are stopped from spreading domestically within a year, according to Maddison.