Ontario has officially declared an end to the measles outbreak that affected over 2,300 individuals across the province for nearly a year, resulting in the tragic death of a newborn. Public Health Ontario and the province’s chief medical officer confirmed on Thursday that the outbreak concluded on Monday, as no new cases had been reported in the past 46 days, surpassing the maximum measles incubation period.
Dr. Kieran Moore, Ontario’s chief medical officer, stated that the final confirmed case in the province developed symptoms on August 21, 2025, after a continuous decline in case numbers over several months, meeting the necessary criteria for ending the outbreak. The outbreak, which originated from exposure to measles in New Brunswick, affected 2,375 individuals in Ontario across 26 local public health units, starting on October 18 of the previous year.
A significant portion of those infected in Ontario were infants, children, and adolescents, with over 96% of them being unvaccinated. During the outbreak, a tragic incident occurred where a baby in southwestern Ontario contracted measles in the womb and passed away after premature birth due to the mother being unvaccinated. Similarly, Alberta has been grappling with a measles outbreak since March, with a recent case involving the death of a premature baby born to a mother who had contracted measles during pregnancy.
As of the latest update, Alberta has reported 1,925 measles cases. While measles was declared eliminated in Canada in 1998, the country risks losing that status on October 27 if continuous transmission persists beyond the specified timeframe.
Dr. Moore emphasized that the end of the outbreak represents a significant milestone but underscored the seriousness and contagious nature of measles. He urged the public to ensure their measles, mumps, and rubella (MMR) vaccinations are up to date, noting that two doses of the MMR vaccine provide nearly 100% protection and have a long history of safe use.
