Four provinces confirm measles cases with Montreal deemed Canada’s epicentre

Seventeen cases of measles have been confirmed in Quebec, Ontario, Saskatchewan and British Columbia — more than half of those in the Montreal area, while one Ontario case has been linked to a high school.

Quebec public health director Dr. Luc Boileau confirmed 10 cases on Monday, almost all of them involving children and making Montreal the country’s epicentre. He said only three of the cases were linked to travel outside of the country, indicating community spread in and around the city.

Public Health Ontario confirmed five cases of measles and said all but one involved travel.

The latest case, announced last week, was in a man in his 30s in the York Region north of Toronto and was “likely” related to community transmission, the region’s medical health officer said.

The man had “close contacts” among students and teachers at a high school so public health officials in that region are ensuring everyone there is vaccinated, Dr. Barry Pakes said.

More than 1,500 students and 150 staff received notification from public health officials on Feb. 29 that they were exposed to a positive case of measles, he said in an email.

Pakes said they were invited to an immunization clinic on Sunday and had “excellent turnout.” The school has a 95 per cent measles vaccination rate “and climbing,” he added.

Students without proof of two doses of the measles, mumps and rubella vaccine will not be allowed to return to school until March 15, Pakes said.

He said the man in his 30s was fully vaccinated. Dawn Bowdish, an immunology professor at Hamilton’s McMaster University, said that it’s rare for someone to be infected after getting vaccinated.

“When I hear about a case like this, I’m thankful this person was vaccinated because it means they probably had a less dangerous course (of illness) than they might have had,” she said, noting that measles is not only the most contagious known virus, but also has the “highest death rate of all the vaccine-preventable infections.”

“The patient would also be less likely to spread measles to others than if he had been unvaccinated,” she said.

Infectious disease specialists say a small number of measles cases can escalate to widespread infections as it has elsewhere in the world, including Europe, where thousands of cases have been confirmed.

Health Canada said that by March 2021, national vaccination coverage rates were similar to those in 2019, with 92 per cent of two-year-olds vaccinated against measles.