How a drop in vaccination rates led to measles outbreaks
Around the world during the COVID-19 pandemic, various countries experienced setbacks in measles surveillance and vaccination efforts, Canada included. That’s a big problem, since measles is the most contagious (yet vaccine-preventable) disease in the world — and uptake rates as high as 95 per cent are needed to curb transmission and prevent outbreaks.
But in many pockets of the country, vaccination rates in recent years have fallen far short.
The measles, mumps and rubella vaccine for children comes in two doses. Coverage for the first dose decreased from about 90 per cent in 2019 to around 83 per cent in 2023, according to the Public Health Agency of Canada. For the second dose, it fell from about 86 per cent to around 76 per cent over the same time period.
Vaccination rates have been even lower in certain communities. In Quebec, for instance, some schools in the Montreal area had uptake as low as 50, 40, or even 30 per cent, officials said last year. It’s been a similar situation in Alberta as well, with uptake as low as 29 or 40 per cent in some areas. Once measles reaches communities like that, it often spreads like wildfire.
