Aggressive measures pay off in York Region
Health unit went into emergency mode after learning its first case had 2,000 potential contacts
Dr. Barry Pakes had one goal after being alerted to York Region’s first measles case of 2024.
The medical officer of health for York Region, home to more than 1.2 million people, wanted to ensure no one else got infected, a daunting but crucial undertaking for such a contagious disease.
And this case, Pakes said, made the task especially difficult.
The man in his 30s worked at a York Region high school with more than 1,850 staff and students. Before his diagnosis, he had dined at a Mississauga restaurant, gone to a walk-in clinic in Woodbridge and sought help at the Cortellucci Vaughan Hospital’s emergency department. People at each of these locations — roughly 2,000 in total — could have been exposed, Pakes said.
It also quickly became clear that York’s first case, confirmed the night of Wednesday, Feb. 28, didn’t know where he had caught the virus, suggesting he had been infected within the community.
Pakes said the health unit went into emergency mode to prevent a measles outbreak, pulling staff from other areas to track down and call close contacts and check the vaccination status of anyone potentially exposed to the virus.
By Thursday evening, a clinic was up and running to get unvaccinated or undervaccinated contacts immunized. Administering a measlescontaining vaccine within 72 hours of exposure to the virus can help prevent people from getting sick. “We have a containment and elimination strategy with measles,” Pakes said. “We are not satisfied if there is a single solitary secondary case. In other words, if that (original) person passes (measles) on to one other person, we think of ourselves as having failed.”
More than three weeks later, Pakes said the “all-hands-on-deck strategy” has paid off. There haven’t been any secondary infections stemming from York’s first case.
“If people are going to get measles it will be within seven to 10 days; 21 days is the outside limit,” he said, adding that he believes the risks from York’s first case have been contained.
“When there’s no secondary cases, when the school doesn’t close, when nobody gets sick, that’s when we’ve been successful. And that’s really what happened in this case.”
Ontario has so far recorded nine cases of measles in 2024. Just seven cases were reported last year in the province. Nationwide, Canada has this year seen at least 41 measles infections, more than three times as many as 2023.
And with measles exploding in Europe and other parts of the world, public health leaders are bracing for more cases in Canada in the weeks following busy March break travel. A key part of their plans, Pakes said, is to ensure they can quickly ramp up their case and contact management systems when cases arise to help contain viral spread.
Contact tracing became a wellknown phrase during the early part of the COVID-19 pandemic. In the first months, each new case prompted public health staff to reach out to close contacts to warn them of potential exposure and advise them to isolate at home with the goal of halting the virus.
But once COVID hit unmanageable levels, public health leaders suspended the measure.
For measles, contact tracing is essential to contain the virus and suppress any outbreaks, Pakes said.
“It’s a lot of work, it’s a lot of resources,” he said. “A large number of cases would mean we would have to redeploy people, as we did during COVID, away from their normal work and into case and contact management.”
Toronto’s first measles case of 2024 — an infant who acquired the illness while travelling outside Canada and who needed hospital care — led to a total of 72 contacts who required follow-up, including 20 who were referred to other health units, Toronto Public Health said.
Peel Public Health said in a statement that staff “followed up with hundreds of identified contacts from the noted exposure sites” of that region’s measles case. Reported to the public on Feb. 14, the case — a child recently returned from international travel — led to possible exposures at two stores, a walk-in clinic and a hospital emergency department in Mississauga.
A spokesperson for the Brant
County Health Unit said it estimates more than 200 people had exposures related to its first case of 2024, a child diagnosed with the virus and hospitalized after travelling to Europe.
“This estimate is based on the exposures at Brantford General Hospital, McMaster Children’s Hospital, and Lufthansa Flight 6584 (cobranded as Air Canada Flight 857),” the spokesperson said.
Pakes said a main goal with York Region’s first measles case was to prevent the closure of the high school while also ensuring the virus didn’t spread. That meant rapidly checking the vaccine status of students and quickly contacting those whose status was unknown. In Ontario, parents are required to submit their child’s immunization records to local public health units or to their child’s school, as required by the Immunization of School Pupils Act.
For contact tracing, staff reach out to those who’ve been exposed to the virus to assess them for symptoms and inquire about their immunization history. Those who aren’t fully vaccinated or who haven’t had a confirmed measles infection are offered a vaccine. Some people are advised to temporarily avoid work, school and other settings and monitor for symptoms.
Pakes said pop-up clinics were held for unvaccinated or undervaccinated contacts to get immunized, with about 50 people in total receiving vaccines.
Three weeks later, Pakes said it’s clear the “aggressive” efforts have worked in York; there have been no secondary cases and the large high school was able to remain open. That the school had an immunization coverage rate of 98.54 per cent definitely helped, he said.