Ontario officially declares the end of a prolonged measles outbreak that affected more than 2,300 individuals and resulted in the unfortunate death of a newborn. Public Health Ontario and the province’s chief medical officer announced on Thursday that the outbreak officially concluded on Monday, as no new cases were reported for 46 days, exceeding the maximum incubation period for measles.
Dr. Kieran Moore stated that the last confirmed case in Ontario was on August 21, 2025, following a continuous decline in case numbers over several months. The outbreak, which originated on October 18 the previous year after exposure to a measles case in New Brunswick, affected 2,375 people across 26 local public health units. New Brunswick had declared its own outbreak over in January.
The majority of those infected in Ontario were infants, children, and adolescents, with over 96% of them being unvaccinated. Tragically, during the outbreak, a baby in southwestern Ontario contracted measles in the womb and passed away after being born prematurely to an unvaccinated mother.
In a similar scenario, Alberta, currently facing a measles outbreak since March, reported the death of a premature baby this month due to the mother contracting measles during pregnancy. Alberta has reported 1,925 measles cases as of now.
While Canada had declared measles eliminated in 1998, this status may be revoked on October 27 due to ongoing transmission. Dr. Moore emphasized the importance of up-to-date measles, mumps, and rubella (MMR) vaccinations, noting that two doses of the MMR vaccine provide nearly 100% protection against this serious and highly contagious disease.
