Six Infants Born with Congenital Measles in Ontario Due to Unvaccinated Mothers

Ontario's chief medical officer of health has revealed that six infants have been born with congenital measles since last fall, tracing their infections to unvaccinated mothers. These cases, linked to an ongoing outbreak, highlight the risks when pregnant individuals remain unprotected against the virus.

Dr. Kieran Moore explained that while all six infants have recovered, their illnesses could have been avoided entirely if their mothers had received the measles, mumps and rubella (MMR) vaccine prior to pregnancy. “If their mothers had been vaccinated, both they and their babies would have been protected,” he emphasized. Congenital measles is a particularly serious concern, as it can lead to severe complications such as inflammation of the brain, long-term disabilities, and even death.

On Thursday, Moore announced the first infant death linked to this outbreak, reporting that a premature baby in southwestern Ontario died after contracting measles in utero. The child also faced other significant medical challenges unrelated to the virus, which contributed to the tragic outcome.

Since the outbreak began in October, over 2,000 cases of measles have been reported across Ontario. Among pregnant individuals, the risk is elevated: Moore confirmed that 40 pregnant people have been infected with measles, of whom only two had received vaccination prior to pregnancy.

The challenge for expecting parents is compounded by the fact that the MMR vaccine, containing a live virus, is not recommended during pregnancy due to potential risks to the fetus. Instead, current guidelines recommend that any unvaccinated pregnant person exposed to measles should receive one dose of intravenous immunoglobulin within six days of exposure. However, Moore acknowledged that vaccine hesitancy often extends to this treatment as well. “Some people, if they don’t want a vaccine, they may not want the immunoglobulin either. That may be a philosophical choice,” he noted.

Health experts are urging isolation for unvaccinated pregnant individuals living in communities experiencing active outbreaks, as a means of limiting exposure. In a recent editorial, Dr. Catherine Varner stressed that pregnant people are disproportionately affected. “Pregnant people are often at higher risk than the general population in infectious disease outbreaks. As such, they cannot be an afterthought in preventive strategies and health-care systems’ responses,” she wrote.

Moore assured the public that most pregnant people in Ontario are fully vaccinated, saying, “It’s only a very small subgroup of people who have chosen not to get vaccinated who are having the complications.” Nonetheless, he acknowledged there is still work to do. “I’d love to have 100 per cent [vaccination], but we have to work with these communities that have chosen not to be vaccinated, and that is a long and difficult conversation that I think all of our health-care workers are dedicated to having.”