Canada Faces Losing measles-Free Status as Outbreak Surges
Canada’s hard-won status as a country free of endemic measles is now in jeopardy, with ongoing transmission of the highly contagious disease infecting over 5,000 people since an outbreak began in New Brunswick in October 2024. The resurgence marks a notable setback for public health officials who spent decades working to eradicate the virus.
The personal toll of measles was stark for generations of Canadians. Dr. Arlene King, a leading public health specialist, vividly remembers contracting the disease over 60 years ago, recalling the debilitating weakness that made even simple tasks like putting on shoes a struggle. Her experience was not isolated; her 18-month-old brother subsequently developed a high fever and suffered a febrile seizure. “It really was not a benign disease,” King stated, underscoring the serious nature of the infection.
Before the introduction of the measles vaccine in 1963, the disease was ubiquitous, with an average of 45,000 cases reported annually between 1924 and 1958, according to a Public Health Agency of Canada report. Outbreaks regularly disrupted communities, forcing school closures and leaving many children with severe complications, including brain inflammation, pneumonia, deafness, and even death.
The arrival of the vaccine dramatically altered the landscape. Cases plummeted to an average of 9,863 per year between 1969 and 1983, and the intervals between outbreaks lengthened. Parents, like Dr. King’s mother,embraced the opportunity to protect their children. This collective effort culminated in the elimination of measles in Canada in 1998 – a milestone achieved through widespread vaccination and robust public health initiatives.
Tho, the current outbreak signals a worrying reversal of progress.physicians who spearheaded the elimination effort express dismay at this disruption, but some remain optimistic that it could galvanize renewed commitment to vaccination.
Early research revealed that a single dose of the measles vaccine wasn’t always sufficient. Dr. Gaston De Serres, a retired medical epidemiologist, discovered that some individuals did not develop immunity after the first dose, but were protected after receiving a second. This phenomenon, explained as primary failure – where the vaccine doesn’t initially trigger an immune response – and secondary failure – where immunity wanes over time – underscored the need for a two-dose vaccination strategy. “If we want to eliminate measles, we have to go to a two-dose programme where those children who did not respond to the first dose would then receive the second dose and be protected,” De Serres explained.
Despite this evidence, Canada was slow to adopt a two-dose approach. A 1996 assessment by the National Advisory committee on Immunization (NACI) characterized the country’s earlier policy as “laissez faire,” noting that Canada lagged behind the United States and other nations in the Americas that had already implemented routine two-dose programs. NACI subsequently recommended a nationwide two-dose program and a mass catch-up campaign.
The resulting campaign, launched in 1996, was a resounding success. Public health nurses vaccinated four million children across the country in just six weeks, often administering shots directly in school gyms. Dr. Monika Naus, who led ontario’s measles elimination program, described it as “probably my proudest achievement in my entire career,” noting the palpable difference it made. Two years later, Canada officially achieved measles elimination status.
Now, the country faces a familiar, yet unsettling, challenge. Dr. James Talbot, alberta’s former chief medical officer of health, draws a parallel between the cyclical nature of measles outbreaks and the endurance required during wartime. “You had to stay sharp, you had to be alert, you had to be prepared to move quickly and get the resources promptly to where they needed to be,” he said. Talbot worries that the unified approach that led to elimination has been lost, but believes a renewed commitment to an evidence-based plan, backed by political will, is essential. “If there’s a recognition that this is a terrible thing…and that it requires an expert evidence-driven plan to fix…then we have a much brighter future for our children.”
This report by The Canadian Press was first published Oct.29, 2025.Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
