Jessica Hopkins is a physician and Public Health Ontario’s chief health protection and emergency preparedness officer.
In 1998, Canada achieved what is known as “measles elimination status,” which means we put an end to the spread of this virus within our borders. This significant public health milestone was the result of families coming together with public health agencies, doctors, nurses, scientists and governments across the country to prioritize ending what was then a common childhood disease.
How did they do it? Vaccines. And why did all of these groups support measles elimination? Because it’s a serious disease and almost entirely preventable.
Complications from measles include ear infections, types of pneumonia and brain inflammation. In the era before the measles vaccine – routine vaccination programs were introduced in Canada in the early 1970s – as many as three out of every 1,000 children with measles died. Most of these children were under five years of age.
The measles vaccine is highly effective even with a single dose. The safety of the vaccine has continued to be demonstrated through years of use. In Ontario, children routinely receive the measles vaccine at one and four years of age. Before 1970, measles was a common childhood disease and people weren’t routinely vaccinated, so most adults born before 1970 have natural immunity and don’t need the measles vaccine.
I am both a public health physician and a family doctor. I have been involved in the public health follow-up of cases and the notification of contacts of many travel-related cases of measles. I feel fortunate that, until now, I had never seen a case of measles caught through community spread in Ontario. So far this year, we have had 13 cases of measles in Ontario. One of those cases did not involve travel outside of Canada, suggesting there has been some level of community spread.
Measles cases are increasing globally. Since October, England has reported more than 1,100 cases (in 2022-23, 84.5 per cent of England’s five-year-old children had received two doses of the measles vaccine.) Closer to home, Quebec has seen 46 cases of measles this year. Media reports put measles vaccine coverage in Montreal schools at around 80 per cent.
While not a perfect measure of vaccine coverage, Ontario monitors the vaccine records of school children, which are reported to local public health units. Prepandemic, records showed that 86 per cent of seven-year-old children had two doses of the measles vaccine. In the 2022-23 school year, these records dropped to 60 per cent. Even more worrisome, the proportion of seven year olds who have no record of even a single dose of measles vaccine increased from 3 per cent to almost 17 per cent.
While some of these children are vaccinated and their records are not up-to-date in the system, it is clear that there are currently more unprotected children than there were prepandemic, and that we are well below the 95-per-cent level of coverage needed for herd immunity (which is the level of coverage needed to protect those who can’t be vaccinated for measles, such as babies under six months of age).
Higher numbers of global cases, increased travel and suboptimal vaccine coverage are creating the ideal conditions for a serious measles outbreak in Ontario. As we face the busy summer vacation and travel season, we need to be vigilant in monitoring for signs of measles. Due to the longer incubation period, which averages 14 days to the start of a measles rash, most people travelling in and out of Canada won’t know they’ve brought the infection home until at least two weeks after they return. People are contagious from four days before the rash starts until four days after – leaving lots of time for the spread of the virus in our communities.
The good news is, we have the tools and experience to limit the impact this virus has on families across Ontario in our schools, daycares and health system. Measles is not the great unknown that COVID-19 was. The key is for all of us to find the space in our busy lives and jobs to make getting the measles vaccine a priority.
The first step is to get kids vaccinated now – in particular, those children who have not had any doses of the measles vaccine. Then we can move on to prioritizing other vulnerable groups. I’ll know we’re on the road to success when I’m busier as a family doctor giving measles vaccines to my patients, than as a public health physician counting measles cases.