The text message on my phone made my heart sink. It was from a colleague at the health unit: “Confirmed measles case at Pearson, Terminal 1. Multiple exposure windows over several days. Public health alert going out tomorrow.“
I’ve been covering public health in Ontario for nearly a decade, but the steady return of vaccine-preventable diseases still feels surreal. Just last week, I interviewed a pediatric infectious disease specialist who warned me that our immunization rates have been slipping dangerously since the pandemic.
Now, Toronto Public Health has confirmed that individuals who passed through Terminal 1 at Canada’s busiest airport during specific time periods between May 30 and June 2 may have been exposed to the highly contagious virus. The case involves an adult traveler who was at the airport while infectious.
“Measles is making a concerning comeback,” Dr. Janice Chen told me when I called her for comment. She’s been working in public health for over 20 years and has witnessed the gradual erosion of our herd immunity firsthand. “What many younger Canadians don’t understand is that we haven’t always had the luxury of not fearing these diseases. When vaccination rates drop below 95%, we create vulnerabilities in our community shield.”
The exposure windows at Pearson were lengthy – spanning from 6:30 p.m. to 10:30 p.m. on May 30, from 11:30 a.m. to 3:00 p.m. on May 31, and from 9:30 p.m. on June 1 to 1:30 a.m. on June 2. During these periods, hundreds, possibly thousands of travelers and airport staff were potentially exposed.
When I arrived at Terminal 1 yesterday, most passengers seemed unaware of the alert. Marie Louie, traveling home to Vancouver with her infant son, looked alarmed when I mentioned the exposure.
“He’s only four months old – too young for the MMR vaccine,” she said, instinctively pulling his blanket up higher. “I thought measles was basically gone in Canada.”
It nearly was. Canada was declared measles-free in 1998, meaning the disease was no longer endemic. But imported cases continue to appear, and with vaccination rates dropping, these cases now find more opportunities to spread.
According to the Public Health Agency of Canada, MMR vaccination rates among 7-year-olds have dropped from 95.2% in 2017 to 91.9% in 2023 – dipping below the threshold needed for herd immunity. The World Health Organization has documented similar concerning trends globally, with measles cases increasing by 18% worldwide in 2023.
“The virus is extraordinarily contagious,” explains Dr. Omar Farid, Chief of Infectious Diseases at University Health Network in Toronto. “If you’re unvaccinated and exposed, you have a 90% chance of contracting it. And you can catch it simply by being in a room where someone with measles was present up to two hours after they’ve left.”
This airborne persistence makes airports particularly dangerous settings for transmission.
In the food court at Terminal 1, I spoke with Raj Patel, who oversees cleaning operations for one of the airport’s contractors. “We’ve increased disinfection protocols since the alert,” he told me, “but measles doesn’t survive on surfaces – it’s in the air. The best protection is vaccination.”
Patel’s team has been fielding questions from nervous travelers all day. “Many people don’t realize that symptoms take 7 to 21 days to appear after exposure. You could be infected and not know it.”
Those exposure windows matter critically. Toronto Public Health is advising anyone who was in Terminal 1 during
