Ontario has officially ended its measles outbreak that affected more than 2,300 individuals over almost a year. The decline in vaccination rates was a significant factor in the outbreak, which tragically resulted in the 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 for 46 days, exceeding the measles incubation period.
Dr. Kieran Moore, Ontario’s chief medical officer of health, stated that the last confirmed measles case in the province occurred on August 21, 2025, after a continuous decrease in case numbers. The outbreak, which originated in New Brunswick and spread to 26 local public health units in Ontario, began on October 18 of the previous year. New Brunswick had declared its own outbreak over in January.
The majority of the measles cases in Ontario affected infants, children, and adolescents, with over 96% of them being unvaccinated. During the outbreak, a baby in southwestern Ontario contracted measles while in the womb and sadly passed away after being born prematurely to an unvaccinated mother. Similarly, Alberta, currently experiencing a measles outbreak since March, reported the death of a premature infant due to the mother contracting measles during pregnancy.
As of the latest update, Alberta has reported 1,925 measles cases. Although Canada declared measles eliminated in 1998, the country risks losing this status on October 27 if continuous transmission persists for 12 months.
Dr. Moore emphasized that the end of the outbreak signifies an essential milestone but warned about the severity and contagious nature of measles. He urged the public to ensure their measles, mumps, and rubella (MMR) vaccinations are up to date, highlighting that two doses of the MMR vaccine provide nearly 100% protection and have a long history of safe use.