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Health Professionals Update – Vol. 18, No. 13

May 21, 2025

From:
Monica Hau, MD, MSc, CCFP, FRCPC
Associate Medical Officer of Health

In this issue:

  • School staff required to have proof of measles immunity in the event of measles exposure
  • Public Health Ontario resource on routine and outbreak-related measles immunization schedules
  • Grade 12 student notification letters for overdue immunizations

Key messages

  • The Chief Medical Officer of Health has requested school boards to advise staff to be prepared to provide proof of measles immunity to public health units in the event of a measles exposure.
  • Public Health Ontario has a new resource on routine and outbreak-related measles immunization schedules.
  • Final notifications to Grade 12 students overdue for childhood vaccinations have been sent with a request to follow-up with their primary care provider to get up to date.
  • Grade 12 students who are overdue for hepatitis B and HPV have until August 31, 2025 to attend a public health clinic for catch-up vaccinations.

School staff required to have proof of measles immunity in the event of measles exposure

The Chief Medical Officer of Health, Dr. Moore, has issued a memo to school boards to advise staff to proactively gather immunization records (or other documentation of immunity) in a timely manner to prevent disruption to school operations.

Schools and childcare centers are high-risk settings for measles outbreaks. If exposed to measles, staff and students are required to provide proof of immunity to public health units before returning to school and/or childcare settings.

Measles immunity by age

  • Adults born before 1970: assumed to have immunity from infection.
    • Action for school staff: adults born before 1970 are generally presumed to have acquired immunity from past exposure to the measles virus. However, some remain susceptible and should be immunized if they are unsure if they had measles or the vaccine.
  • Adults (18+ years) born on or after 1970: may have received up to two doses of measles vaccine.
    • Action for school staff: a second dose of MMR vaccine is recommended (if not previously received). If exposed to measles, staff need documented proof of immunization of two measles vaccines or immunity bloodwork to return to school within 21 days of the exposure.

*Please note for school staff born outside of Ontario, the measles immunization schedule may vary.

Accessing historical immunization records from public health units

Prior to 2014, immunization records were maintained by each individual health unit. Therefore, school staff are advised to check with the public health unit where they attended school to see if they are able to access their immunization records. Staff who attended school in Peel region may call 905-791-7700 and select option #2 (Routine School Vaccines) between 8:30am - 4:30pm, Monday-Friday, and ask to speak to a member of the immunization records team.

Re-immunizing patients with MMR

Individuals without record of receiving a measles vaccine may be considered unimmunized and can receive dose(s) of the MMR vaccine. Offering a measles vaccine is preferred to ordering serology to determine immune status. It is safe to receive doses of the MMR vaccine even if patients have received this vaccine previously.

Checking measles immunity

Checking serology for measles IgG immunity may be an option for individuals who decline further measles vaccination or have contraindications to receiving live vaccines (e.g. pregnancy, immunocompromised individuals).

Public Health Ontario resource on routine and outbreak-related measles immunization schedules

Public Health Ontario has developed a resource for clinicians on routine and outbreak-related measles immunization schedules: Routine and Outbreak-related Measles Immunization Schedules. Please note that the Wellington-Dufferin Guelph health unit borders Peel region and is considered to be a high-risk area for measles outbreaks.

Grade 12 student notification letters for overdue immunizations

Final notifications to Grade 12 students overdue for immunizations against the nine diseases required under the Immunization of School Pupils Act have been sent with a request to follow-up with their primary care provider to get up to date.

  • Grade 12 students who are overdue for hepatitis B and HPV have until August 31, 2025 to attend a public health clinic for catch-up vaccinations.
  • Students remain eligible for meningococcal vaccine until vaccine is received.
  • Appointments may be booked online: Region of Peel - eBooking.

Contact us

The Health Professionals Update (HPU) is distributed to physician offices in Peel region via fax or email. Share this update with other health professionals in your clinic.

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