Canada is no longer measles-free because of , international health experts said Monday, as childhood vaccination rates fall and the highly contagious virus spreads across North and South America.
The loss of the country鈥檚 measles elimination status comes more than a year after the started spreading.
Canada has logged 5,138 measles cases this year and two deaths. Both were babies who were exposed to the measles virus in the womb and born prematurely.
is a symbolic designation, but it represents a hard-won battle against the infectious disease. It is earned when a country shows it stopped continuous spread of the virus within local communities, though occasional cases might still pop up from travel.
Measles with a high fever followed by a telltale rash that starts on the face and neck. Most people recover, but it鈥檚 one of the leading causes of death among young children, according to the World Health Organization. Serious complications, including blindness and swelling of the brain, are more common in young children and adults over age 30.
It is prevented by a vaccine administered routinely and safely to children around the world.
鈥淚t’s a deeply disheartening development. It’s a deeply worrisome development. And, frankly, it’s an embarrassing development,” said Jennifer Nuzzo, a Brown University infectious disease expert. 鈥淣o country with the amount of resources of Canada 鈥� or other countries in North America even 鈥� should lose their measles elimination status.鈥�
Vaccination campaigns led to elimination
Canada eliminated measles in 1998, followed by the United States two years later. After hugely successful , the Americas became the first region in the world to be free of measles in 2016. Health officials estimate the measles vaccine prevented in the Americas between 2000 and 2023.
But vaccination rates have since slipped below the 95% coverage rate needed to stop outbreaks. Large outbreaks in Venezuela and Brazil in 2018 and 2019 cost the region its elimination status. It was reclaimed in 2024, but ends again with Canada鈥檚 loss.
Experts from the Pan American Health Organization, an independent health agency, made the determination after analyzing data on Canada鈥檚 outbreaks that showed the virus has spread continuously for a year.
It has never been easy to stop measles from circulating in local communities, Dr. Jarbas Barbosa, director of the Pan American Health Organization, said in a briefing Monday.
鈥淎s a region, we have eliminated measles twice,鈥� Barbosa said. 鈥淲e can do it a third time.鈥�
In a statement, Canadian health officials said they were working with government and community partners to improve vaccination coverage, share data and provide evidence-based guidance.
The virus is one of the most contagious known to medicine. One infected person can spread it to up to 9 out of 10 unprotected people they come into close contact with. Health experts say, by far, the best prevention against measles is the vaccine, which provides 97% protection after two doses.
Barbosa’s organization has confirmed nearly 12,600 cases this year across 10 countries, a 30-fold increase from 2024. The vast majority are in Canada, the U.S. and Mexico, but Bolivia, Brazil, Paraguay, and Belize also have active outbreaks.
In 2024, the region had a 79% vaccination rate, an increase from years past but still too low, he said.
United States could be next to lose status
The U.S. eliminated measles in 2000. That status is at risk even though the large outbreak that and sickened nearly 900 across , and Oklahoma earlier this year is over.
Current outbreaks in the U.S. include 34 cases in South Carolina and one hitting towns on the Arizona-Utah border that has sickened more than 150 since mid-August.
A major question now is if either are linked to the Texas outbreak. To lose elimination status, health data must show a continuous chain of measles spread for one year.
International health officials have recommended the U.S. 鈥渆nhance case investigation protocols,鈥� because closing data gaps is key to stopping the virus from taking hold again, said Dr. Daniel Salas, who leads immunization efforts at the Pan American Health Organization.
The U.S. Centers for Disease Control and Prevention has confirmed 1,681 cases and 44 outbreaks this year, making it the worst year for measles in the U.S. in more than three decades. Only nine states haven鈥檛 confirmed cases, according to the CDC.
A large outbreak also continues in Chihuahua, Mexico, where health officials have confirmed 4,430 cases as of last week and 21 deaths, according to state health data.
Mexican and U.S. officials have said the genetic strains of measles spreading in Canada match those in the Texas and Chihuahua outbreaks. All those outbreaks affected certain Mennonite Christian communities who trace their migration over generations from .
In August, officials said Mennonite communities in Belize, Argentina, Bolivia, Brazil, and Paraguay had outbreaks of the same type of measles virus.
Mennonite churches do not formally discourage vaccination, though historically have low vaccination rates and a distrust of government.
It’s tempting to look at the outbreaks in a vacuum, Nuzzo said. But many are likely linked, she said, not just by sick people traveling but also by anti-vaccine disinformation.
鈥淚t’s not a religious prohibition in most of these cases,鈥� she said. “It is just people being, perhaps, distrustful of authorities, but also preyed upon by these anti-vaccine influencers who profit off of the fears that some people may have.”
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