Ontario's Measles Outbreak Exceeds Cases in the U.S.

Over the years, Ontario's measles cases have been rare, owing to the high immunization coverage. However, that favorable situation has changed in Canada's most populous province.

This new report from the public health ministry describes the epidemiology of measles in Ontario, focusing on the current multi-jurisdictional measles outbreak.

As of March 26, 2025, 557 measles cases (464 confirmed, 93 probable) had been reported in Ontario since October 28, 2024.

This is a significant change from the past decade.

Between 2013 and 2023, 101 confirmed measles cases were reported in Ontario, while 64 cases were reported in 2024.

Just to the south in the United States, Minnesota, Michigan, Ohio, Pennsylvania, and New York have also reported measles cases, but on a far reduced scale.

In 2025, a total 483 confirmed measles cases were reported by 20 U.S. jurisdictions.

As of March 30, 2025, the U.S. Centers for Disease Control and Prevention maintains a global measles outbreak Watch-Level 1, Notice, which does not include Canada.

The CDC recommends that most people get two doses of the MMR vaccine to protect against this infectious disease. Measles vaccines are generally available at travel clinics and pharmacies in the U.S.