Statement from the Chief Medical Officer of Health

“It is with deep sadness that I confirm that an infant, born prematurely and infected with measles, has tragically passed away in southwestern Ontario. The infant contracted the virus before birth from their mother, who had not received the measles, mumps and rubella (MMR) vaccine. While measles may have been a contributing factor in both the premature birth and death, the infant also faced other serious medical complications unrelated to the virus. Out of respect for the family’s privacy, no further personal or medical details will be shared.

I extend my heartfelt condolences to the family during this incredibly difficult time. I also want to thank the dedicated health-care professionals who cared for both the mother and infant with compassion and expertise.

Measles poses a serious risk to unvaccinated individuals and to infants in the early stages of life in particular. Measles is one of the most contagious diseases and can lead to severe complications, including pneumonia, brain swelling, premature birth and in rare cases, death.

Anyone who is unvaccinated is at risk and I urge everyone, but especially those who may become pregnant, to ensure they have received two doses of the MMR vaccine, which will protect both a parent and baby. This vaccine has been safely used for over 50 years and is highly effective. Two doses provide nearly 100 per cent protection.

Children who live outside of southwestern Ontario should receive their first dose of measles-containing vaccine at 12 months of age and a second between four and six years old. Children and adults who live in southwestern Ontario should be vaccinated according to the outbreak vaccination schedule, which includes an early dose of MMR vaccine for infants six to 11 months of age.

If you are unsure of your or your child’s vaccination status, please contact a health-care provider or local public health unit. If you suspect you or a family member may have measles, call your health-care provider or local public health unit for advice. If you require medical attention, call ahead before visiting a health-care facility to help prevent further spread. If you are pregnant, have not previously received two doses of MMR vaccine and may have been exposed to measles, contact your health-care provider for further guidance.

Since October 28, 2024, Ontario has reported a cumulative total of 2009 measles cases linked to an outbreak that began in New Brunswick. As of June 3, 2025, this includes 1729 confirmed and 280 probable cases, with 140 hospitalizations. The vast majority of cases are among individuals who are unvaccinated or whose immunization status is unknown.

We will continue to work closely with local public health partners to monitor and respond to this outbreak and to protect the health and safety of all Ontarians.”