Canada is no longer measles-free due to ongoing outbreaksInternational health experts said Monday as childhood vaccination rates fall and a highly contagious virus spreads across the Americas.
The country's loss of measles elimination status occurred more than a year after highly contagious virus began to spread.
There have been 5,138 measles cases and two deaths in Canada this year. Both were infants who were exposed to the measles virus in the womb and were born prematurely.
Measles elimination It's a symbolic designation, but it represents a hard-won battle against an infectious disease. It is earned when a country proves it has stopped the ongoing spread of the virus among local communities, although isolated cases may still arise during travel.
Measles usually starts with a high fever followed by a characteristic rash that begins on the face and neck. Most people recover, but it is one of the leading causes of death among young children, according to the World Health Organization. Serious complications, including blindness and brain swelling, are more common in young children and adults over 30 years of age.
It can be prevented with a vaccine that is given regularly and safely to children around the world.
“It's a very discouraging event. It's a very troubling event. And frankly, it's an embarrassing event,” said Jennifer Nuzzo, an infectious disease expert at Brown University. “No country with the resources of Canada—or even other North American countries—should lose its measles elimination status.”
Canada eliminated measles in 1998, followed by the United States two years later. After huge success vaccination campaignsIn 2016, America became the first measles-free region in the world. Health officials believe the measles vaccine prevented 6.2 million deaths in America between 2000 and 2023.
But vaccination rates have since fallen below the 95% coverage needed to end outbreaks. Large outbreaks in Venezuela and Brazil in 2018 and 2019 cost the region its eliminated status. It was returned in 2024, but again ended in a loss to Canada.
Experts at the Pan American Health Organization, an independent health agency, made the decision after analyzing data from outbreaks in Canada that showed the virus had been spreading continuously for a year.
Stopping the spread of measles in local communities has never been easy, Dr. Jarbas Barbosa, director of the Pan American Health Organization, said at a briefing Monday.
“As a region, we have eliminated measles twice,” Barbosa said. “We can do this a third time.”
In a statement, Canadian health officials said they are working with the government and community partners to improve vaccination coverage, share data and provide evidence-based recommendations.
The virus is one of the most contagious known to medicine. One infected person can infect up to 9 out of 10 unprotected people with whom they come into close contact. Health experts say the best way to prevent measles today is a vaccine, which provides 97% protection after two doses.
Barbosa's organization has confirmed nearly 12,600 cases this year in 10 countries, 30 times more than in 2024. The vast majority are in Canada, the United States and Mexico, but Bolivia, Brazil, Paraguay and Belize also have active outbreaks.
The region's vaccination rate was 79% in 2024, which is higher than in previous years but still too low, he said.
The United States eliminated measles in 2000. This status is under threat, even despite a major outbreak that killed three and almost 900 people fell ill around the world Texas, New Mexico and Oklahoma ended earlier this year.
Current outbreaks in the U.S. include 34 cases in South Carolina and one affecting towns along the Arizona-Utah border, where more than 150 people have fallen ill since mid-August.
The big question now is whether they are related to the outbreak in Texas. To lose elimination status, health data must show an unbroken chain of measles transmission within one year.
International health officials have recommended that the U.S. “improve case investigation protocols” because closing data gaps is key to preventing a resurgence of the virus, said Dr. Daniel Salas, who leads immunization efforts at the Pan American Health Organization.
The US Centers for Disease Control and Prevention has confirmed 1,681 cases and 44 outbreaks this year, making it the worst year for measles cases in the US in more than three decades. Only nine states have not confirmed cases, according to the CDC.
A large outbreak also continues in Chihuahua, Mexico, where health officials confirmed 4,430 cases last week and 21 deaths, according to state health data.
Mexican and U.S. officials said genetic strains of measles spreading in Canada matched measles outbreaks in Texas and Chihuahua. All of these outbreaks affected certain Mennonite Christian communities, who trace their migration back generations from From Canada to Mexico to Seminole, Texas.
In August, officials said there were outbreaks of the same type of measles virus in Mennonite communities in Belize, Argentina, Bolivia, Brazil and Paraguay.
However, Mennonite churches do not formally discourage vaccinations. more conservative Mennonite communities historically have low vaccination rates and distrust of government.
“It’s tempting to look at outbreaks in a vacuum,” Nuzzo said. But many of them are likely related not only to sick people traveling but also to anti-vaccine misinformation, she said.
“In most cases, it’s not a religious prohibition,” she said. “It’s just that people may not trust the authorities, but they are also falling prey to these anti-vaccination influencers who are preying on the fears that some people may have.”
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