Medical Advisory: Measles Activity, Prevention and Preparedness

Current situation:

Hamilton Public Health Services has reported its first lab-confirmed case of measles in 2025. This case does not have a source of infection or known epidemiologic link at this time. There continues to be increased measles activity in Southwestern Ontario including neighbouring jurisdictions, with most cases being in unimmunized and under- immunized children and adolescents.

Measles Vaccination:

• Ensure patients and staff are up to date with measles-containing vaccines according to the Publicly Funded Immunization Schedules for Ontario:
  • Two doses of measles-containing vaccine are routinely given at 12 months of age (after the first birthday) using measles, mumps, rubella (MMR) vaccine and at 4 years of age using measles, mumps, rubella, varicella (MMRV) vaccine.

• Those who are behind on routine vaccinations, including MMR, should follow an age appropriate catch-up vaccination schedule.

  • If travelling to areas where there is a high risk of measles exposure, including internationally and areas of Ontario currently experiencing a measles outbreak, infants between 6 and 11 months of age can receive a single dose of MMR vaccine. Hamilton is not currently considered an area experiencing a measles outbreak.
    • Two doses are still required after twelve months of age to complete the series.
  • Adults who have only received one dose of MMR vaccine are eligible to receive a second dose if they meet any of the criteria below or based on the healthcare provider’s clinical judgement.
    • Health care workers
    • Post-secondary students
    • Individuals planning to travel to areas where risk of measles exposure remains a concern.
  • Parents and guardians must report childhood vaccinations, including

  measles-containing vaccines, to Public Health directly. Maintaining up-to-date vaccination records supports the management of measles contacts. Hamilton residents can report their vaccines here: https://www.hamilton.ca/reportingvaccines

Suspect measles in a patient with:

• Febrile illness and rash
  • History suggesting they are not immune to measles, particularly if they
    • Travelled
    • Are known to have had an epi-link to a measles case or outbreak
  • Other indicators which raise clinical suspicion for measles include:
    • Prodrome (i.e. cough, runny nose and conjunctivitis/watery eyes) followed by a non-itchy rash which begins on the face and then spreads downward
    • Progression of the rash (i.e. macular or maculopapular to confluent red blotchy appearance)
    • Koplik spots

(Public Health Agency of Canada, 2024)

Infection Prevention and Control (IPAC) recommendations for suspect measles cases:

• Only staff known to be immune to measles should provide care.

Note: Hospitals and health care provider offices should ensure all staff are up-to- date with either 2 doses of documented measles vaccination OR documented laboratory evidence of immunity, regardless of age, as per the Canadian Immunization Guide, Measles vaccine.

• All health care providers should wear a fit-tested, seal-checked N95 respirator upon entry to the room.
• Patients who phone for an assessment should be screened at time of booking for measles symptoms and seen at the end of the day.
• Ask the patient to wear a medical mask upon entry to the building and to wear the mask until they leave the building.
• Immediately isolate the patient in an exam room. Patients should not wait in the common waiting room. The exam room door should be closed. Place a sign at the entrance to the room. Do not use the room for 2 hours after the patient leaves.
• If testing a patient for suspect measles, patient should be placed in home isolation for 4 days after the onset of rash (onset of rash is considered day 0), or until directed otherwise by Public Health.
• For patients requiring private lab testing, please call the lab ahead of time to arrange for appropriate IPAC measures. Instruct the patient to wear a mask while at the lab, and call the lab before they enter.
• If the patient is acutely unwell and requires assessment at an emergency department, health care providers should call in advance so appropriate IPAC measures can be put in place. Patients should advise the emergency department via phone or an asymptomatic caregiver that they have arrived before entering.

Laboratory Testing Information:

Report all suspect measles cases to Hamilton Public Health Services by calling the Infectious Disease Program

Table 1: Measles Testing