Measles update for health care providers
Advisory Alert
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To: Local Health System Partners
March 25, 2025
Background
The incidence of measles has been rising globally and provincially. Currently, a measles outbreak is affecting multiple communities in Southwestern Ontario. Among individuals with measles in this outbreak, 85.1% are unimmunized and 10.6% have an unknown immunization status.
Consider measles in the differential diagnosis of respiratory symptoms or rash, particularly in those with recent travel to higher-risk areas, including Southwestern Ontario.
Resources
Immunization and testing
- Routine measles immunization: Immunization is the best way to protect against measles. Ensure patients, especially children, are up to date with measles vaccinations in accordance with the Publicly Funded Immunization Schedules for Ontario.
- Individuals can view and update their immunization records by visiting phsd.ca.
- Other considerations for measles immunization: Additional or early measles vaccination may be considered for individuals travelling outside of Canada or to Southwestern Ontario, based on individualized risk assessment. Most individuals travelling to Southwestern Ontario continue to be at low risk of measles exposure. See the section on Travellers in the Canadian Immunization Guide Measles chapter for more information.
- MMR vaccine may be administered as early as 6 months of age. If MMR is administered prior to 12 months of age, 2 additional doses of measles-containing vaccine must be administered after the child is 12 months old.
- Testing: Diagnostic testing for measles includes (1) nasopharyngeal/throat swab for PCR, (2) urine for PCR, AND (3) diagnostic serology (IgG and IgM). Specimens for PCR can be stored in the fridge between 2 to 8 degrees for up to 72 hours. Specimens pending transport should be reported to Public Health. For more information, please see measles specimen storage (Public Health Ontario).
- Infection prevention and control: For information about IPAC, refer to the Measles IPAC Checklist for Clinics and Specimen Collection Centres (PDF) (Public Health Ontario).
- Additional resources:
- See the Advisory Alert issued March 2024, which includes information on immunization, clinical presentation, and testing.
- Measles: Information for Health Care Providers (PDF) (Public Health Ontario)
- Updated recommendations on measles post-exposure prophylaxis (NACI)
Data
- Measles and Measles Exposures in Ontario (Public Health Ontario)
- Measles Weekly Monitoring Reports – Canada (Government of Canada)
Reporting to Public Health
Measles and other diseases of public health significance are reportable. If you suspect, or are testing clients for measles, notify Public Health by faxing or emailing the reporting form (PDF) to 705.677.9618 or HPT_FAX_confidential@phsd.ca, in addition to calling the number below, as applicable.
For questions about measles or other communicable diseases, please contact the Control of Infectious Disease Program at 705.522.9200, ext. 772 (toll-free 1.866.522.9200). For immunization inquiries, call the Vaccine Preventable Diseases program at 705.522.9200, ext. 458 (toll-free 1.866.522.9200). Both programs are available Monday to Friday, 8:30 a.m. to 4:30 p.m., or after-hours and on weekends at 705.688.4366.
Sincerely,
Original Signed By
Emily Groot, MD, MPH, FRCPC
Acting Associate Medical Officer of Health
Note: All Advisory Alerts are found on our website
This item was last modified on March 25, 2025