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Canada has formally lost its measles elimination status, the country’s public health agency announced Monday, meaning all of the Americas have lost that status as well. The decision, which was widely expected, comes after a meeting last week where an expert committee of the Pan American Health Organization determined that a large measles outbreak that began in Canada in October 2024 was still ongoing, more than 12 months after it started. Advertisement PAHO, the regional office for the Americas of the World Health Organization, was scheduled to hold a press conference later Monday to explain the decision. Canada’s loss of measles elimination status has reverberations for the Americas, the only region of the WHO that has ever achieved measles-elimination status. PAHO first gained measles-free status in 2016, only to lose it two years later after a long-running outbreak in Venezuela. It regained measles-free status in 2024. Advertisement Countries that have been declared measles free are always at risk of having imported cases of measles, in the form of returning travelers or tourists who are infected. Such cases, which are often one-offs, do not threaten a country’s measles-elimination status. But if an imported case triggers a chain of transmission that continues for over a year, measles-elimination status is lost. In its statement, the Public Health Agency of Canada said it is “collaborating with the PAHO and working with federal, provincial, territorial, and community partners to implement coordinated actions — focused on improving vaccination coverage, strengthening data sharing, enabling better overall surveillance efforts, and providing evidence-based guidance.” Canada has recorded more than 5,100 measles cases this year alone; most are associated with the ongoing outbreak, which is occurring in interlinked religious communities that avoid contact with the outside world. Members of these communities have few interactions with the health care system, resulting in extremely low vaccination rates among both children and adults. To date there have been two deaths in the Canadian outbreak, in infants born with congenital measles. (They were infected in the womb.) Canada could regain its measles-free status once the current outbreak is extinguished, after a period of 12 months. But while the outbreak has slowed markedly in recent weeks, it is still ongoing. In the most recent week for which data are available — the week ending Oct. 25 — there were 29 new cases of measles in four provinces.
