Measles the 'most transmissible infection on the planet,' warns expert

Amid a growing number of measles outbreaks in the United States and Europe, health officials are warning the public about the possibilities of outbreaks in Canada, with one infectious disease specialist saying even a few measles cases can spark an outbreak.

"We have to remember that measles is a very, very transmissible infection," Dr. Isaac Bogoch, a Toronto-based infectious disease specialist, told CTV News Channel. "Probably the most transmissible infection on the planet."

On Wednesday, Ontario’s top doctor issued a warning to public health units saying they should prepare for more cases and “potential outbreaks” of measles.

Chief Medical Officer of Health Dr. Kieran Moore says "given this dramatic rise in cases globally, health system partners in Ontario must be prepared."

He said he also expects the "continued importation of cases" and his memo urges health-care practitioners to encourage vaccinations with March Break vacations coming up.

Bogoch says that measles "isn't a benign infection" and warns it can cause "significant morbidity and mortality," particularly for children.

"It kills 140,000 people per year on the planet," Bogoch explained. "Most of them are kids, all of these are preventable."

Canada's ideal vaccination rate

The measles vaccine is "safe and freely available," but according to Bogoch, the country needs to maintain vaccination rates "above 90 per cent, preferably above 95 per cent" to avoid outbreaks in Canada.

However, he warns that because of the COVID-19 pandemic, "many people have missed routine vaccinations," and is urging the public to "check those vaccine cards."

He's also warning those born before 1996 to double-check their vaccination status. Why? That's the year the second dose of the measles vaccine was "really rolled out."

"Some people might think they've had two doses, but they might only have had one dose."

What's the risk for Canada?

Measles is a viral infection that spreads through the air and close contact. Symptoms start to present anywhere from seven to 21 days after exposure.

Bogoch says "there are always pockets" where vaccine rates are lower, which means those places are "susceptible to outbreaks," and he warns that rising anti-science and anti-vaccination movements mean more are choosing "not to vaccinate themselves or their children.

With the World Health Organization saying there's been an alarming rise in measles globally, Bogoch says keeping vaccination rates high is key for Canada, particularly in an age of "incredible human mobility."

"This is a growing problem," he says. "This infection will find a way."

With files from CTV News Toronto's Katherine DeClerq.