In a significant public health setback, Canada has officially lost its hard-won measles-free status. The Pan American Health Organization (PAHO), the World Health Organization's regional office for the Americas, revoked the designation on 10 November 2025. This decision follows a severe measles outbreak that has infected thousands across the country over the past year.
What does 'measles-free' status actually mean?
The loss of this status is more than just a title; it's a stark indicator of a deteriorating public health situation. To be considered measles-free, a country must demonstrate no ongoing local transmission of the disease for at least one year. Measles is one of the most contagious diseases on the planet. Before the vaccine was introduced in 1963, it infected nearly every child and caused over 2 million childhood deaths annually.
The vaccine led to a dramatic reduction in cases. By 1968, just five years after its introduction, cases in the United States had dropped by more than 95%. Canada achieved its measles elimination status in 1998, followed by the US in 2000. The entire Americas region was declared measles-free by 2016, though it temporarily lost this status in 2018 after outbreaks in Brazil and Venezuela.
The root of the problem: Falling vaccination rates
The resurgence of measles is directly linked to a decline in childhood immunisation. To achieve herd immunity and prevent outbreaks, approximately 95% of the population needs to be vaccinated against measles.
However, in Canada, vaccination rates have been falling. The percentage of two-year-olds who received at least one dose of the measles vaccine fell from around 90% in 2019 to just 82% in 2022 and 2023. This drop, exacerbated by the COVID-19 pandemic, left a growing number of people vulnerable.
The consequences have been severe. After recording only 16 total cases between 2020 and 2023, Canada saw cases jump to over 100 in 2024 and a staggering more than 5,000 cases in 2025. Infections have occurred in every province, resulting in the tragic deaths of two infants. Alarmingly, fewer than 10% of those who fell ill had been vaccinated.
A warning for the United States and beyond
Epidemiologists warn that Canada's situation is not an isolated incident. The United States is on a similar trajectory and is likely to lose its own measles-free designation in 2026.
Despite a kindergarten vaccination rate above 90%, this has proven insufficient to prevent outbreaks. An outbreak that began in Texas in January 2025 infected more than 760 people and killed two children. In total, the US has recorded over 1,600 measles cases across more than 40 states in 2025—the highest number since 1992. More than 90% of these cases were in unvaccinated individuals.
Mexico, with thousands of cases this year, is also expected to lose its measles-free status. While Central America, South America, and the Caribbean currently retain their status, the outbreaks in North America significantly increase the risk of the virus spreading further.
This troubling trend points to a deeper issue: a declining trust in public health messaging and science. Without a significant improvement in vaccination coverage and public confidence, many countries face the prospect of more frequent and larger outbreaks of measles and other vaccine-preventable diseases in the coming years.
