Measles outbreak causes Canada to lose elimination status

A measles outbreak in Ontario, concentrated in undervaccinated communities with close cross-border social networks, resulted in 2,377 cases, 166 hospitalizations, 13 ICU admissions, 51 pregnancies affected, and one infant death, leading Canada to lose its measles elimination status in November 2025.

Why it matters. The outbreak demonstrates that even high-income countries can lose measles elimination status when immunity gaps persist in specific communities, posing risks of cross-border spread and resurgence of a disease previously controlled.