Six infants have been born in Ontario with congenital measles since a provincial outbreak began last fall, according to the province’s chief medical officer of health, Dr. Kieran Moore. The babies were infected in the womb after their mothers, who were unvaccinated, contracted measles during pregnancy. Although the infants have recovered, Moore emphasized that the cases were entirely preventable.
Congenital measles is a serious condition that can lead to life-threatening complications such as brain inflammation and, in some cases, death. Just last week, an infant born prematurely in southwestern Ontario who had contracted measles died, although doctors noted the baby was also battling unrelated severe medical issues.
Moore revealed that, to date, 40 pregnant individuals in Ontario have been diagnosed with measles, with only two having been vaccinated. He urged unvaccinated pregnant people to isolate themselves if they reside in communities facing active outbreaks. More than 2,000 measles cases have been reported across Ontario since the outbreak began in October 2024.
Due to the live virus in the measles, mumps, and rubella (MMR) vaccine, it is not recommended during pregnancy. However, the National Advisory Committee on Immunization advises that unvaccinated pregnant individuals exposed to measles should receive intravenous immunoglobulin within six days. Moore noted that hesitancy around this preventative treatment often mirrors resistance to vaccines, describing it as a “philosophical choice” for some.
In a Canadian Medical Association Journal editorial published Monday, Dr. Catherine Varner stated that pregnant people are “bearing the burden” of the outbreak, calling on health-care systems to prioritize their protection during public health crises.
Moore acknowledged that most pregnant individuals in Ontario are vaccinated, with only a small unvaccinated subset facing complications. He said reaching 100 per cent vaccination is the goal, but achieving that requires persistent, compassionate outreach to hesitant communities—a task health-care workers remain committed to.