After Decades of Elimination, Measles Returns to Canada
In 1998, measles was officially eliminated in Canada, with the United States following two years later. However, two and a half decades later, the disease has resurfaced in the public spotlight with 1,912 cases in the US in 2025, compared to just 285 in 2024 and 59 in 2023. The initial outbreaks in the US received relatively large amounts of media coverage, while just north of the border, Canada is grappling with its own measles crisis. Despite having a population eight times smaller than that of the US, Canada reported nearly three times as many measles cases in 2025. The recent resurgence of measles in Canada raises an urgent question: If measles was once eliminated, how did it return, and what can Canada do to regain its elimination status?
A highly contagious virus, measles infected 10,000 to 90,000 people per year in Canada before the release of the measles vaccine in 1963. Infection was nearly universal, with a cross-sectional study of British Columbians reporting 97 per cent seropositivity in the cohort born between 1957 and 1970 and 99 per cent seropositivity in the cohort born prior to 1957. Seropositivity indicates a positive result for the presence of measles antibodies in an individual’s blood, indicating prior infection by measles. The near-total seropositivity of individuals born prior to the widespread availability of the measles vaccine exhibits just how widespread the disease was. The universality of measles, combined with the fact that the disease killed one in 1,000 children, made the disease an immensely large public health challenge.
With the introduction of the measles vaccine in the 1960s and a concerted public health campaign, Canada achieved elimination status in 1998. Importantly, unlike eradication, elimination only entails that the disease is no longer found or transmitted within a certain region. Eradication, on the other hand, means the disease is not spread anywhere on earth, which has only been achieved twice—once with smallpox in 1980, and again with rinderpest, a cattle disease, in 2011.
Because measles was eliminated and not eradicated, there always remains the risk that the virus will regain a foothold if public health efforts are not sustained. Canada’s last measles peak, a 2011 outbreak primarily in central Quebec with 750 cases, threatened to jeopardize Canada’s elimination status. The current outbreak is concentrated mostly in Alberta and Ontario; the Ontario outbreak starting when an individual contracted measles at a Mennonite gathering in New Brunswick before returning home. The virus then spread through low German-speaking communities in Southwestern Ontario.
These low-German-speaking communities are a subset of the larger Mennonite community in Canada. Mennonites are a Christian group with roots dating back to the 16th century in the Netherlands and Germany. Mennonite communities are highly diverse in their practices, with some living modern lives while others, in more conservative groups, limit their use of technology and modern medicine. It is within these conservative Mennonite communities, where vaccination rates have historically been rather low, that the virus was spread; in fact, nearly all those who were infected in Ontario were unvaccinated.
As the outbreak began to subside in Ontario, the number of cases in Alberta increased rapidly, peaking at 151 cases between April 27, 2025, and May 3, 2025. As of December 6, 2025, Alberta accounted for 1,987 of Canada’s 5,329 cases, representing 37 per cent of all cases, despite comprising only 12 per cent of the population. Similar to Ontario, Alberta also has a large Mennonite population, estimated at 25,000-30,000. In southern Alberta, which hosts a large portion of the Mennonite community, only 56 per cent of children have received two doses of the MMR vaccine, while 32 per cent have received none.
Yet the drop in vaccination rates that has permitted the revival of the endemic spread of measles in Canada cannot be solely attributed to the low-German-speaking Mennonite communities of Ontario and Alberta. Since the COVID-19 pandemic, vaccine hesitancy has been linked to increased mistrust in the healthcare system and a rise in misinformation. This increase in hesitancy is evident in Alberta’s major cities, Calgary and Edmonton, where even in the most vaccinated districts, vaccination rates are in the high 70s or barely reach 80 per cent. Generally, measles vaccination rates have been falling across Canada, with the number of two-year-olds receiving at least one measles dose falling from 90 per cent to 82 per cent between 2019 and 2022.
As a result of more than 5,329 measles cases in 2025, compared with just 16 during 2020-2023, Canada officially lost its measles-free status, as recognized by the Pan American Health Organization. While embarrassing for Canada’s health system, the US and Mexico may also risk losing their measles elimination status, as they are facing their own measles outbreaks, albeit to a lesser extent.
The loss of Canada’s measles-free status is a much more than a symbolic tarnish on its image; it also puts some of the most vulnerable Canadians at risk. Those who are immunocompromised or medically unable to get the vaccine, like those under the age of one, are now at a much greater risk of contracting the disease—even if they are outside the communities where most of the transmission is occurring. The hospitalization of children who are experiencing complications provides an easy mechanism for intercommunity spread.
With no reported cases in Alberta since December 13, 2025, and in Ontario since December 6, 2025, the brunt of the outbreak appears to be over; however, Canada is still not out of the woods, as new cases are being reported in Manitoba and Quebec. Although Canada seeks to regain its measles elimination status, this may take time. Although only the absence of disease spread within Canada is required, it took until 2024 for Brazil and Venezuela to regain their elimination status after losing it in 2018 and 2019, respectively.
While a potentially long road lies ahead for Canada to eliminate measles from within its borders once again, some public health experts believe it is well within the country’s abilities to do so. As we see increasing investment in Canada’s public health system, rebuilding confidence in vaccinations is just one of the tools at the country’s disposal to get rid of measles like they once did in 1998.
Edited by Maisie Minnick
Featured Image: “Pink and White Flower Petals” by the CDC is licensed under the Unsplash License.
