Updated measles vaccine recommendations for new outbreak affected areas may result in increased immunization requests

Article

May 13, 2025

Halton Region Public Health: Office of the Medical Officer of Health

The Ministry of Health has updated measles vaccine recommendations (external PDF) for certain health units due to an increased risk of exposure in those areas. Halton Region is not currently experiencing outbreak-related cases of measles.
People who live, work, attend school, travel, worship or spend time in these affected areas are recommended to receive measles vaccine according to the recommendations below:
- Chatham-Kent
- Grey Bruce
- Lambton
- Middlesex-London
- Waterloo
- Wellington-Dufferin-Guelph
- Windsor-Essex
- Southwestern
- Grand Erie
- Huron Perth
Some child care centres and schools in these areas have issued communications to patients advising them of the updated vaccine recommendations so you may receive increased immunization requests.

Children 6 to <12 months	Can receive an early first dose of MMR. Note: Children still need two more doses after 12 months of age.
Children under 4 years old (who have had one dose)	Can get an early second dose of MMR (at least 4 weeks after the first dose). Note: No further doses re required after this second dose. Will still require varicella at age 4.
Adults born in or after 1970	Should receive a second dose of MMR if they have only had one

Health care workers without documentation of proof of immunity, regardless of age of birth, will be excluded from work if exposed to a confirmed measles case. Ensure all staff in your office/clinic have documentation of either two doses of measles-containing vaccine OR laboratory evidence of immunity.
Health care workers or military personnel: Two doses of the measles vaccine are recommended regardless of year of birth.

All Ontarians are eligible for one or two publicly funded doses of measles-containing vaccine depending on their age and risk factors. Refer to the Publicly Funded Immunization Schedule for Ontario for details on routine, high-risk and catch-up schedules.
MMRV vaccine is publicly funded as part of the routine immunization schedule for individuals 4 to 6 years of age and for catch-up immunizations for individuals 7 to 12 years of age. While MMRV can be used for outbreak, case and contact management purposes, due to the limited provincial supply of MMRV vaccine, the Ministry of Health is asking that MMRV be used primarily for routine or catch-up immunizations.
Ensure children who may have missed dose(s) of measles-containing vaccine during the pandemic years are brought up to date as soon as possible.
If immunization records are unavailable, immunization with measles-containing vaccine is preferred over serology. Refer to PHO Measles-Serology (external link) for details. Serology is not recommended before or after receiving MMR. If serology is inadvertently done, and the patient does not demonstrate immunity but has the required number of doses, re-immunization is not necessary.
Travellers to destinations outside of Canada should ensure they are adequately immunized against measles prior to travel. Refer to Canadian Immunization Guide (external link) for recommendations.