Quebec health officials report 10 cases of measles in Montreal area, confirm community spread

Montreal has become the epicentre of measles cases in Canada, and the disease is spreading in Quebec for the first time since 2019, public health officials said Monday.

There are now 10 confirmed cases of the virus in the province, all in the greater Montreal area, Dr. Luc Boileau, Quebec’s public health director, told reporters.

“Three are directly linked to international travel, there are several others that are likely linked to one another, but we can suspect that there are some that could only have been acquired in the community,” he said. 

Boileau said people who took their children to the emergency room of the Saint-Justine children’s hospital in late February may have been exposed. He said Montreal public health has published on its website a list of potential exposure sites, including medical clinics and a flight from Casablanca, Morocco, that arrived in Montreal Feb. 24.

Ten cases are cause for concern, he said, because the virus is highly transmissible, adding that people become contagious four days before they develop a rash common to the disease.

“It’s the beginning: 10 cases. Outbreaks like this don’t begin with 1,000 cases, they usually begin with a few cases,” he said.

As of Friday, there were only three reported cases of the measles in the province. 

Dr. Mylene Drouin, Montreal’s public health director, said officials are concerned that some schools in the city have measles vaccination rates as low as 30 per cent. Montreal schools, she added, have an average vaccination rate of 80 per cent, lower than in other parts of the province. Drouin said officials want to increase rates to 95 per cent.

Not since 2019 has a case of measles been detected in Montreal, said Drouin, who added that public health officials across North America have worked to eradicate the disease.

Measles was declared eliminated in Canada in 1998.

Dr. Caroline Quach-Thanh, a pediatric infectious disease specialist at the Sainte-Justine hospital, told the same news conference that 2019 was also the last time there was any transmission of measles in Quebec. Measles has a mortality rate of around one in 3,000, she said. 

Around 10 per cent of children who are infected with the disease develop pneumonia and around one in 1,000 develop a brain inflammation, Quach-Thanh said, adding that even relatively minor infections in babies can lead to potentially deadly brain inflammation 10 to 20 years after infection.

“There are enough complications and worries that what you want is for your child not to catch measles, so if we’re able to curtail this outbreak, then we should,” Quach-Thanh said. 

Officials encouraged unvaccinated Quebecers to make sure they and their children get the vaccine.

“If you’re appropriately vaccinated — so two doses after the age of 12 months — you’re usually absolutely well-protected against a resurgence of the disease and if you do develop the disease, because sometimes it happens, we do have breakthrough, like in everything else, then the risk of complications is almost zero,” Quach-Thanh said. 

In Ontario, public health officials reported on Monday five lab-confirmed measles cases. Four of those — in the regions of Windsor-Essex, Peel, Brant and Toronto — were related to travel. The latest case, announced on Feb. 29, involved a man in his 30s in York Region who was “likely” infected through community transmission, the region’s medical officer of health said on Monday.

“Given we do not know the source of where this individual acquired measles infection, nor did this individual have any travel history, it is likely they may have been exposed to it by someone in our community,” Dr. Barry Pakes said in an emailed statement.

One case of measles has been reported in British Columbia. 

This report by The Canadian Press was first published March 4, 2024.

— With files from Nicole Ireland in Toronto.

Jacob Serebrin, The Canadian Press