Public Health Update for Clinicians: Response to Measles Risk

As of March 20, 2025, the Windsor-Essex County Health Unit is recommending healthcare providers (HCPs) conduct individual risk assessments for patients 6-12 months of age, who have not started the recommended series of Measles, Mumps, Rubella (MMR) vaccine in accordance with Ontario’s Publicly Funded Immunization Schedule. Based on the level of individual risk, as assessed through the patient’s likelihood of travel to areas where measles is circulating, or other high-risk activities (e.g., attending large gatherings), HCPs should consider administering a dose of MMR ahead of schedule. This dose would be an additional dose to the existing recommended series outlined in Ontario’s Publicly Funded Immunization Schedule and Canadian Immunization Guide.

In addition to the new recommendation above, the WECHU continues to encourage health care providers to take the following actions: 

1. Ensure that all vaccination schedules for children and youth clients are kept up to date and vaccines are given on time, in accordance with the publicly funded schedule, to ensure protection as early and effectively as possible.
2. Continue to encourage unvaccinated individuals to get vaccinated and stay up to date as per Publicly Funded Immunization Schedules for Ontario and the Canadian Immunization Guide.

As a reminder, the MMR vaccine eligibility is outlined in the Ontario’s Publicly Funded Immunization Schedule:

• Adults born after 1970 that have never been immunized with Measles-containing vaccine should contact their health care provider for assessment and vaccine recommendation.
• Adults born before 1970 can be presumed to have acquired natural immunity to measles; however, susceptible health care workers, travelers to destinations outside of Canada, and military personnel should contact their health care provider to discuss the need for an MMR vaccine.

1. Ensure any patient’s identified as having been exposed to a suspected or confirmed case of measles are instructed to contact the WECHU to be assessed for eligibility for post-exposure prophylaxis.

Ongoing Further Recommendations

1. Screen patients over the phone for signs/symptoms of measles at the time of booking an appointment. Make efforts to arrange appointments for symptomatic patients at the end of the day, when no other patients are present.
2. Provide signage outside the entrance to your facility asking clients to self-screen for signs and symptoms of measles and wear a mask on entry.
3. Consider Measles as a Differential Diagnosis when patients present with febrile illness and rash, history suggesting that they are not immune to measles (not fully vaccinated (i.e. 2 doses of MMR) or lack of confirmed measles or protective serology), and/or history of travel to areas with measles outbreak or are known to have had an epidemiologic link to a measles case or outbreak.
4. Ensure your office has testing specimen containers, supplies, and requisitions for testing all 3 measles tests: Nasopharyngeal Swab/Throat Swab, Urine and Serology. Check expiry dates of your specimen kits. Additional kits can be ordered from Public Health Ontario Lab.
5. Report suspected or confirmed cases of communicable diseases to WECHU as soon as possible using the reporting forms on the WECHU website. Fill out forms completely and fax to 226-783-2132.
6. Check immunity status of staff at your facility. Only staff immune to measles should provide care.
7. Ensure you have N95 masks available for staff and that your staff have been fit-tested. All health care providers, regardless of presumptive immunity to measles are to wear a fit-tested, seal-checked N95 mask when providing care to clients with suspect or confirmed measles.
8. Review the “Clinical Office Checklist for Measles” and “Measles resources for Health Care Providers” for  more recommendations and information.

For questions or concerns, please call 519-258-2146 ext. 1420 during regular office hours, and 519-973-4510 during after-hours and weekends. You can also visit our website.
 
For more information, visit:

1. Public Health Ontario, 2025: Enhanced Epidemiologic Summary. Measles in Ontario
2. Government of Canada, 2025: Measles and Rubella Weekly Monitoring Report. Week 7 (February 9 to February 15, 2025)
3. Measles: For Health Professionals
4. Ministry of Health, 2024: Appendix 1: Case Definitions and Disease Specific Information: Measles
5. Public Health Ontario, 2025: Measles Information for Clinicians
6. Government of Canada, 2025, Measles vaccines: Canadian Immunization Guide