What is the risk of catching measles during summer travel? Here’s what experts say

Canadian infectious disease expert Stacey Smith? says the risk of measles spreading is 'very high' during summer travel.

As more Canadians travel during the summer amid rising cases of measles both domestically and throughout the world, one infectious disease expert says the risk of it spreading is “very high.”

“The problem is people are unvaccinated and the more that we travel, the more we spread it around,” Stacey Smith?, whose expertise includes the mathematical modelling of infectious diseases at the University of Ottawa, said in a video interview with CTVNews.ca on Wednesday.

Smith?, who uses a question mark as part of her name to differentiate from others with a similar name, called rising measles cases “a powder keg waiting to happen.”

“So the only reason we’re not living in a massive measles pandemic is because we’ve had very successful vaccine programs for many, many decades now,” Smith? said.

According to the University of British Columbia’s faculty of medicine, measles is up to six times more infectious than COVID-19.

Smith?’s warning comes as another top infectious disease expert is sounding the alarm about the higher risk in the United States during the peak months of travel.

Dr. Tina Tan, a professor at Northwestern University in Chicago, said it’s a “public health crisis” in Canada, the U.S. and other countries with measles outbreaks, noting infected people can get “extraordinarily ill” and even die from it.

“If they are unvaccinated and they’re travelling to an area where there are a number of measles cases, they are at increased risk for being exposed and possibly getting measles,” said Tan, who is president of the Infectious Disease Society of America, in a video interview with CTVNews.ca on Wednesday.

Tan said measles is a bigger threat when more unvaccinated people are travelling and are exposed to infected people.

“Any country has the same risk with more travel occurring during the summer,” Tan said.

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Who is most at risk?

The Canadian government says the risk of catching measles is high for those who visit areas where the highly contagious disease is spreading and didn’t develop immunity from it from vaccines or past infections.

“Currently there is widespread measles transmission ongoing in many countries and Canadians may be exposed traveling abroad,” the Public Health Agency of Canada (PHAC) wrote in an email to CTVNews.ca. “Canadians should ensure they are protected if traveling outside Canada.”

Most people who have caught measles this year in Canada were exposed to the virus in the country, with 3,311 cases as of June 28, according to the latest federal government data. The 52 cases from outside the country stemmed from travel to Afghanistan, Bahamas, Cambodia, Czech Republic, England, France, India, Italy, Kenya, Mexico, Pakistan, Philippines, Romania, Somalia, South Korea, Uganda, United States and Vietnam.

Jeffrey Pernica, a pediatric infectious disease specialist at McMaster Children’s Hospital and McMaster University in Hamilton, Ont., said people who visit areas with ongoing outbreaks, including in British Columbia, Alberta, Manitoba and Ontario, face a higher risk of getting measles, especially if they are not vaccinated or not immune to the disease.

Pernica added that there’s a risk regardless of whether they travel domestically or internationally.

“Right now, Canada is having some difficulties with measles outbreaks,” said Pernica in a video interview with CTVNews.ca on Wednesday, noting Canada has more measles cases than the United States and other countries in the Americas. “The safest thing for most Canadians is to make sure that their immunizations -- measles and otherwise -- are up to date.”

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Overall risk in Canada ‘moderate’

Despite the warnings, the Canadian government said all countries, including Canada, currently have a level 1 travel health notice for measles, the lowest risk level. A level 1 notice recommends that people practise health precautions, including ensuring they have updated routine vaccinations.

Still, cases are at a 27-year high in Canada, with more than 3,700 reported as of June 28 this year compared to only 17 for all of 1998.

PHAC said it is continuing to monitor the situation and has assessed the overall risk to be “moderate.” It said that within the country, there has been an ongoing spread of measles related to travel.

Measles was eliminated in Canada in 1998, which means any new cases are imported from other countries but these cases are stopped from spreading domestically within a year, according to PHAC.

But PHAC said Canada could lose its elimination status if the situation doesn’t change by November.