Measles a rising concern in Canada, following near-zero years during pandemic

During the pandemic, measles rates dropped to almost zero cases per year in Canada. What went up, according to one infectious disease expert, was vaccine hesitancy.

There were only 12 measles cases in Canada in 2023, but this year there have already been 81. Rising cases and dwindling vaccination rates are cause for concern, said Dr. Susy Hota, the division head of infectious diseases and medical director of infection prevention and control at University Health Network in Toronto.

"A trend that we're noticing since the pandemic especially is that there's been an increase in hesitancy to get vaccines that we normally gave out through childhood," said Hota.

After widespread vaccination, measles was essentially eliminated in Canada by 1998, Hota told CTVNews.ca in an interview on Wednesday. Cases that do appear in Canada almost always originate from travel to another country — but as cases rise, that starts to change.

"You'll start to see other cases pop up here and there where you can't trace it directly back to travel," she said. "And that's what we want to avoid, because that gets really, really tricky when you have these sporadic cases that you didn't expect to occur."

Hota says the target should be at least 95 per cent of the public fully vaccinated against measles, which means one dose for young children and two doses for school-aged children.

In Canada, though, the numbers fall short. The latest available data from the 2021 childhood National Immunization Coverage Survey estimates 91.6 per cent of two-year-olds have their measles vaccine — but that number is only 79.2 per cent for seven-year-olds having both doses.

Hota says it's more concerning for communities with even lower vaccination rates, which she says are especially vulnerable to outbreaks from the highly contagious illness.

“Once the case gets imported into that group, it can spread quite easily, because if you're susceptible to measles and you get exposed to it, you've got a 90% chance of contracting the illness,” she said.

Measles in North America

An ongoing measles outbreak in Oregon has health officials urging parents to get their children vaccinated as they head back to school. It's the state's worst outbreak in more than 30 years, and the U.S. as a whole has seen 236 measles cases this year, compared to just 59 in 2023.

In Canada this year, the measles spike has been even worse, with about three times as many cases per capita as the United States, according to data from the Public Health Agency of Canada and the U.S. Centers for Disease Control and Prevention.

There were almost zero measles cases in Canada during the pandemic, but as travel restrictions eased, the country started seeing infections again.

One of those cases resulted in the death of a young child in Ontario, the first death the province had seen since tracking began in 1989.

Before the 1960s, measles case rates were routinely more than 500 per 100,000 people -- a number that dropped about tenfold in the 1970s, when the one-dose MMR vaccine was introduced. After the introduction of the two-dose vaccine in the 1990s, the rate dropped to effectively zero.

Hota says the main thing people can do to prevent measles from spreading is staying on top of immunization guidelines for children.

"It's important to ensure that kids get vaccinated as early as possible," Hota says. "Children are at greater risk for complications of measles and that's what we really want to try to avoid."

Children who missed a routine vaccination during the pandemic should be caught up, she says. And anyone who is unsure of their own status should check with their doctor — especially before travelling.

Other than the distinctive rash, early symptoms include "fever, malaise, cough, coryza (runny nose) and conjunctivitis," according to Public Health Canada.

Hota says anyone visiting another country who comes back with symptoms should contact their health care provider before showing up to a clinic or hospital.

"We get these sporadic cases from travel, and we really, really want to avoid the possibility of that resulting in any additional cases."