Canada has lost its measles elimination status after 12 months of continuous transmission of the highly infectious disease, the Pan-American Health Organization (PAHO) announced on Monday.

This follows a PAHO expert meeting on infectious diseases last week, the Measles, Rubella, and Congenital Rubella Syndrome Elimination Regional Monitoring and Re-Verification Commission.

“The commission determined that endemic measles transmission has been re-established in Canada, where the virus has circulated for at least 12 months,” PAHO director Dr Jarbas Barbosa told a media briefing.  

Since Canada’s measles outbreak started in October 2024, there have been over 5,000 cases in nine of the country’s 10 provinces.

The Public Health Agency of Canada said in a statement on Monday  that it is “currently experiencing a large, multi-jurisdictional outbreak of measles that began in October 2024 with cases in Alberta, British Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec, Saskatchewan, and the Northwest Territories.”

“While transmission has slowed recently, the outbreak has persisted for over 12 months, primarily within under-vaccinated communities,” it added.

Thirty-fold increase

Canada’s loss is also PAHO’s loss, as the entire World Health Organization’s Region of the Americas has also lost its measles elimination status as a result.

As of 7 November, 12,593 confirmed measles cases have been reported across 10 countries (approximately 95% in Canada, Mexico and US) in the region, PAHO reported.

This is a 30-fold increase compared to 2024. Twenty-eight deaths have been recorded: 23 in Mexico, three in the United States, and two in Canada.

“Measles is the most contagious disease known to humankind,” said Barbosa. “One infected person can transmit the disease to up to 18 others. Thanks to vaccines, many people have never seen an outbreak in their lifetime.”

Measles can cause severe complications such as blindness, pneumonia, encephalitis and even death. 

“Stopping the spread of measles required that at least 95% of the population be vaccinated with two doses. This is very important across all communities, without exception,” Barbosa stressed.

However, in 2024, regional coverage for the second dose of the measles, mumps and rubella vaccine (MMR2) averaged 79%. Only 31% of countries reached 95% or more coverage for the first dose, and just 20% achieved that level for the second dose.

There are active measles outbreaks in Canada, Mexico, the United States, Bolivia, Brazil, Paraguay, and Belize. 

Canada has lost its measles elimination status…a sad milestone.

Now is the time to double down on lowering barriers to routine childhood immunizations and ensuring Canadians have access to credible, science-based information.

Link: https://t.co/JbALpkKWSW pic.twitter.com/JMiySJCOuM

— Isaac Bogoch (@BogochIsaac) November 10, 2025

Mostly in the unvaccinated

“Transmission has primarily affected under-vaccinated communities, with 89% of cases occurring in unvaccinated individuals or those with unknown vaccination status. Children under one year of age are the most affected, followed by those aged one to four years,” said PAHO.

“Vaccination remains the most effective means of protection. Over the past 25 years, the measles vaccine has prevented more than six million deaths across the Americas —and an estimated 15 million deaths over the last 50 years,” stressed PAHO.

To regain its measles elimination status, Canada must show that it has eliminated endemic transmission for at least 12 consecutive months, supported by comprehensive vaccination, surveillance, and outbreak-response data.

Canada will present and implement an action plan under PAHO’s regional framework, focused on boosting immunisation coverage, reinforcing surveillance systems, and ensuring rapid outbreak response to stop endemic transmission and regain measles elimination status, said PAHO.

PAHO is providing technical support to countries to strengthen surveillance, laboratory diagnosis, outbreak response, and vaccination campaigns. Experts have been deployed to Mexico, Argentina, and Bolivia, and it is monitoring risks in Belize, Brazil and Paraguay.

Image Credits: Health Canada .