Ontario Declares Measles Outbreak Over: Routine Immunization Resumes
Earlier this month, Ontario’s Chief Medical Officer of Health announced that Ontario’s measles outbreak had officially been declared over. Click here to read the memorandum. This decision was made in alignment with Public Health Agency of Canada (PHAC) guidelines, whereby a measles outbreak can be declared over when no new outbreak-related cases have been reported for 46 consecutive days. The last reported outbreak-related case in Ontario had onset of rash on August 21, 2025.
With the outbreak declared over, the outbreak immunization strategy in highly impacted public health units has been discontinued, and Ontario’s routine Publicly Funded Immunization Schedule should again be followed across the province. Children receive two doses of measles-containing vaccine, given at least 28 days apart, after 12 months of age and again at 4-6 years of age. Per the routine immunization schedule, infants 6-11 months who are travelling internationally or to areas of Canada where measles is of concern can receive the vaccine, with two additional doses required after 12 months of age to achieve long-term immunity.
Reporting Confirmed or Suspected Measles Cases
Although the multijurisdictional outbreak has been declared over in Ontario, measles activity continues in other regions of Canada and internationally. Ongoing vigilance is required when assessing patients presenting with symptoms of measles. Ontario is expected to continue to see occasional measles infections, similar to previous years, and Ottawa has identified additional measles infections since the outbreak was declared over. Report all persons being tested for measles, and all suspected or confirmed cases of measles immediately to Ottawa Public Health:
- During business hours Monday to Friday 8:30am to 4:30pm: Call 613-580-2424 ext. 24224. Please leave a detailed, confidential message including your contact information and a Public Health Nurse will call you back.
- After hours and holidays: Call 3-1-1 and ask for the Communicable Disease Manager on-call.
Vaccination is the best way to protect against measles, with two doses providing nearly 100% protection. Please continue to encourage your patients to get up to date with their measles, mumps, and rubella (MMR) vaccinations.
For more information on measles epidemiology, symptoms, testing, management and vaccination, visit Measles - Ottawa Public Health.
Physician & NP Resources
- Measles -Ottawa Public Health: Ottawa Public Health offers clinical resources on measles epidemiology, symptoms, testing, management, and vaccination to support your care.
- Report measles, suspected or confirmed cases, to Ottawa Public Health.
Emily Cahill
Ottawa Public Health