Quebec measles outbreak linked to declining vaccination rates

Measles is making a comeback in Quebec. From December to March, at least 31 cases were reported and experts point to one cause — declining vaccination rates.

"The unifying theme for all of these places as to why measles is causing outbreaks or is out of control is very simple: low vaccination rates," said Dr. Donald Vinh, an infectious disease specialist at the McGill University Health Centre (MUHC).

Data from Quebec public health, obtained by Radio-Canada, shows vaccination rates declined during the COVID-19 pandemic.

"It's true that during the pandemic, there was difficulty of access. And access is really the key to making vaccination as easy as possible for parents," said Dr. Nicholas Brousseau, a physician with the Institut national de santé publique du Québec (INSPQ).

Montreal has the lowest vaccination rate in the province at 85 per cent pre-pandemic and 83 per cent in 2024.

A sharp drop in vaccination rates occurred around 2021-22 in many areas during the pandemic, particularly in Montreal at 79.2 per cent and the Laurentians at 84.6 per cent.

The Laurentians and the Montérégie region have both continued to have low vaccinations rates, despite a recent uptick.

In Nunavik, rates fluctuate, but are currently strong. The rate jumped from 74.4 per cent in 2015-16 to over 97 per cent in recent years, data from the Quebec vaccination registry shows.

"It's not that people are against the vaccine, it's that people don't have access," Vinh said.

Measles spreads through the respiratory tract and can be fatal, particularly for infants and those who are pregnant or have weakened immune systems.

Children typically receive the vaccine at 12 and 18 months, but it remains available free of charge at any age. Experts warn that 95 per cent vaccination coverage is needed to prevent outbreaks.

"Eighty-three, 89 — all of these values may seem good on paper, but it's not at least 95 per cent, and that's why you're getting all of these outbreaks," Vinh explained.

Trying to increase vaccination rates is an ongoing effort throughout Quebec.

"We always have to maintain those efforts because measles is so contagious that when more and more children are not vaccinated, transmission can start again," Brousseau said.