Canada loses Measles-free status.

Canada has officially lost its Measles-free status, according to a press release issued by the Pan American Health Organization on 10 November 2025. The decision came following a meeting of the Measles, Rubella, and Congenital Rubella Syndrome Elimination Regional Monitoring and Re-Verification Commission in Mexico City between 4 and 7 November, which heard that the Measles Virus has been circulating in Canada for at least 12 months. This finding also ends the Measles-free status of the wider Americas region, the second time this has happened, despite the region being the first to gain such a status in 2016. The first loss was caused by an outbreak in Venezuela in 2018, with the region regaining Measles-free status in 2024.

The Measles, Rubella, and Congenital Rubella Syndrome Elimination Regional Monitoring and Re-Verification Commission heard that there have been 12 596 confirmed cases of Measles in the Americas between 1 January and 7 November 2025, with ten countries being affected. However, 95% of these cases have occurred in three countries, Canada, the United States, and Mexico. There have also been 28 recorded deaths due to the Virus, 23 in Mexico, three in the United States, and two in Canada.

There are still active outbreaks in six countries in the region,  Canada, Mexico, the United States, Bolivia, Brazil, Paraguay, and Belize, mostly thought to be triggered by imported cases. Under-vaccinated communities have been particularly badly hit, with 89% of cases affecting unvaccinated people or people of unknown vaccination status. The most affected group are children under one year of age, with the second most affected group being children aged one-to-four.

The Canadian outbreak began in New Brunswick in October 2024, and has since spread to every province of Canada. As of November 2025 the disease is still circulating in four provinces, Alberta, British Columbia, Manitoba, and Saskatchewan.

Measles is a human disease caused by a Virus in the Paramyxovirus family. The Virus infects the respiratory tract, then spreads throughout the body. It can lead to major epidemics with significant morbidity and mortality, especially among vulnerable people. Among young and malnourished children, pregnant women, and immunocompromised individuals, including those with HIV, cancer or treated with immunosuppressives, Measles can cause serious complications, including severe diarrhoea, blindness, encephalitis, pneumonia, and death.

Thin-section transmission electron micrograph revealing the ultrastructural appearance of a single Viron, of the Measles Virus. The measles Virus is a Paramyxovirus, of the genus Morbillivirus. It is 100-200 nm in diameter, with a core of single-stranded RNA, and is closely related to the Rinderpest and Canine Distemper Viruses. Two membrane envelope proteins are important in pathogenesis. They are the F (fusion) protein, which is responsible for fusion of virus and host cell membranes, viral penetration, and hemolysis, and the H (hemagglutinin) protein, which is responsible for adsorption of virus to cells. Centers for Disease Control and Prevention/Wikimedia Commons.

Transmission is primarily person-to-person by airborne respiratory droplets that disperse rapidly when an infected person coughs or sneezes. Transmission can also occur through direct contact with infected secretions. Transmission from asymptomatic exposed immune persons has not been demonstrated. The Virus remains contagious in the air or on contaminated surfaces for up to two hours. A patient is infectious from four days before the start of the rash to four days after its appearance. There is no specific antiviral treatment for Measles, but most people recover within 2-3 weeks.

An effective and safe vaccine is available for prevention and control. The Measles-containing-vaccine first-dose is given at the age of nine months, while the Measles-containing-vaccine second dose is given at the age of 15 months. A 95% population coverage of Measles-containing-vaccine first-dose and Measles-containing-vaccine second dose is required to stop measles circulation.

In areas with low vaccination coverage, epidemics typically occur every two to three years and usually last between two and three months. However, their duration varies according to population size, crowding, and the population’s immunity status.

Vaccination against Measles is estimated to have prevented more than six million deaths in the Americas over the past 25 years. However, it is estimated that in 2024 regional cover for the second dose of the vaccine had fallen to 79%, well below the 95% coverage thought necessary to prevent the disease circulating. It is estimated that only 31% of countries in the Americas Region achieved 95% coverage for the first dose of the Measles vaccine, and that only 25% reached that level for the second dose.

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