Canada: Measles in Ontario

Public Health Ontario reports a total of 57 confirmed and 6 probable cases of measles in 2025 as of February 12.

Most of these cases were associated with an ongoing multi-jurisdictional outbreak—on October 18, 2024, exposure to a travel-related case in New Brunswick led to outbreaks of measles in New Brunswick and Ontario. While New Brunswick declared their outbreak over on January 7, 2025 , Ontario continues to experience measles transmission, which has also led to cases of measles in Manitoba.

As of February 12, 2025, 99 cases of measles (67 confirmed, 32 probable) have been reported in Ontario in association with this outbreak.

One confirmed case in 2025 was associated with travel (i.e. acquired measles outside of Canada) – this case was an unimmunized child who required hospitalization.

Outbreak cases have occurred in four public health units: Southwestern Public Health, Grey Bruce Health Unit, Grand Erie Public Health [formerly Brant County Health Unit and Haldimand Norfolk Health Unit], and Chatham-Kent Public Health.

All outbreak cases were in individuals born in or after 1970; 84 were in children and adolescents, and 15 in adults- among children and adolescents, 98.8% were unimmunized.

Seven outbreak cases have required hospitalization, and all were unimmunized children.

Prior to the COVID-19 pandemic (2013–2019), the annual number of measles cases in Ontario ranged between seven and 22; in comparison, one case was reported during the pandemic (2020–2022) while seven cases were reported in 2023.

In neighboring Quebec, 13 measles cases have been reported through February 1.

Measles is a highly contagious respiratory virus. Symptoms of measles include fever, a red blotchy rash, red watery eyes and cough. Immunization is the best protection against measles. For children and most adults born in or after 1970, this means receiving two doses of measles containing-vaccine (e.g., MMR vaccine).