Title: Ontario's Measles Outbreak Declared Over After Nearly a Year

TORONTO - Ontario's measles outbreak, which affected over 2,300 individuals and resulted in the death of a newborn, has officially ended. Public Health Ontario and the province's chief medical officer announced on Thursday that the outbreak concluded on Monday, following 46 days without new reported cases. This period is twice the maximum incubation time for measles.

Dr. Kieran Moore, Ontario's chief medical officer of health, stated, "In Ontario, the last confirmed case developed a rash on August 21, 2025, following several months of steadily declining case numbers. We have now surpassed the required threshold with no additional cases identified."

The outbreak began on October 18 of last year after exposure to a measles case in New Brunswick, which declared its outbreak over in January. The spread of the virus infected 2,375 people across 26 local public health units in Ontario. Nearly 75% of those infected were infants, children, and adolescents, with over 96% being unvaccinated.

Tragically, during this outbreak, a baby in southwestern Ontario contracted measles in utero and died after the mother, who was unvaccinated, gave birth prematurely. In a related incident, Alberta reported the death of another premature infant earlier this month due to maternal measles infection. Alberta has recorded 1,925 measles cases since March.

Measles was declared eliminated in Canada in 1998, but the country risks losing that status on October 27 if continuous transmission persists for 12 months. In addition to the outbreak, Ontario has seen 43 measles cases this year that were not linked to the outbreak, with three cases reported in September.

The Public Health Agency of Canada indicates that while most cases in 2025 have been in Ontario and Alberta, infections have also occurred in every province, with one case reported in the Northwest Territories. No cases have been documented in Yukon or Nunavut.

Dr. Moore emphasized the importance of vaccination, stating, "Although the end of the outbreak marks an important milestone, measles is a serious and highly contagious disease." He urged residents to ensure their measles, mumps, and rubella (MMR) vaccinations are current, noting that two doses of the MMR vaccine provide nearly 100% protection and have been safely used for decades.