Public Health Update for Clinicians: Response to Measles Risk

As of April 23, 2025, there are over 70 cases of measles in the Windsor-Essex County (WEC) area. To ensure that susceptible clients (under-immunized or unimmunized), with exposures to a case of measles, have access to postexposure prophylaxis (i.e. vaccination) in a timely and client-centered way, the WECHU is requesting the support of all WEC health care providers in the provision of these important doses of vaccine. If clients of your practice or health care facility contact your office requesting appointments for post-exposure doses of MMR vaccine, it is important for those doses to be provided within the recommended post-exposure timelines to be effective. The WECHU will continue to guide susceptible contacts about the timelines within which a dose of vaccine can be administered, and we encourage providers to plan whenever possible to support this immunization. For information on infection prevention and control recommendations refer to Public Health Ontario’s Measles IPAC Checklist for Clinics and Specimen Collection Centres.

If you are interested in supporting the community as a host site for ongoing postexposure prophylaxis measles vaccination for individuals without access to a health care provider, please contact the WECHU at 519-258-2146 ext. 1420 for additional information. 

In addition to the support request 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. 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.
3. 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.

• 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.

4. 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.
5. 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.
6. 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.
7. 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.
8. 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. Incomplete forms will be returned to you to be completed.
9. Check the immunity status of staff at your facility. They should receive MMR vaccines if they are not fully vaccinated or immune.
10. 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 symptomatic patients with suspect or confirmed measles.
11. Review the “Clinical Office Checklist for Measles” and “Measles resources for Health Care Providers” for more recommendations and information.

Reference: Ontario Ministry of Health: Roles and Responsibilities in Addressing the Ongoing Provincial Measles Outbreak.

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.