Canada loses measles elimination status after ongoing outbreak
Canada is no longer measles-free due to an ongoing outbreak, with childhood vaccination rates falling and the highly contagious virus spreading across North and South America, international health experts said Monday.
The country’s loss of measles elimination status comes more than a year after the highly contagious virus began spreading.
Canada recorded 5,138 cases of measles this year and two deaths. Both were children who were exposed to the measles virus in utero and were born prematurely.
Measles elimination is a symbolic name, but it represents a hard-won battle against the infectious disease. It is acquired when a country demonstrates that it has stopped the ongoing spread of the virus within local communities, although occasional cases may arise from travel.
Measles usually begins with a high fever followed by a 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 age 30.
It is prevented by a vaccine that is routinely and safely given to children around the world.
“It’s a very disappointing development. It’s a very troubling development. And frankly, it’s an embarrassing development,” said Jennifer Nuzzo, an infectious disease expert at Brown University. “No country with the scale of resources that Canada has — or even other countries in North America — should lose measles elimination status.”
Vaccination campaigns have eliminated them
Canada eliminated measles in 1998, and the United States followed two years later. After hugely successful vaccination campaigns, the Americas became the first region in the world to be measles-free in 2016. Health officials estimate that the measles vaccine prevented 6.2 million deaths in the Americas between 2000 and 2023.
But vaccination rates have since fallen below the 95% coverage rate needed to stop the outbreak. Massive outbreaks in Venezuela and Brazil in 2018 and 2019 cost the region elimination status. It was reclaimed in 2024, but again ended in Canada’s loss.
Experts from the Pan American Health Organization, an independent health agency, made the decision after analyzing data related to the outbreak in Canada that showed the virus spreading continuously for a year.
It has never been easy to stop the spread of measles in communities, Dr. Jarbas Barbosa, director of the Pan American Health Organization, said at a news conference on Monday.
“As a region, we have eliminated measles twice,” Barbosa said. “We can do it a third time.”
Canadian health officials said in a statement they are working with the government and community partners to improve vaccination coverage, share data and provide evidence-based guidance.
The virus is one of the most contagious viruses known in medicine. An infected person can infect up to 9 out of 10 unprotected people with whom they come in close contact. Health experts say that the best way to prevent measles so far is the vaccine, which provides 97% protection after two doses.
Barbosa has confirmed nearly 12,600 cases this year in 10 countries, a 30-fold increase from 2024. The vast majority of them are in Canada, the United States and Mexico, but Bolivia, Brazil, Paraguay and Belize are also seeing active outbreaks.
He said that in 2024, the region’s vaccination rate is 79%, which is an increase from previous years but still very low.
The United States may be next to lose ground
The United States eliminated measles in 2000. That status is in jeopardy even though a large outbreak that killed three people and sickened nearly 900 in Texas, New Mexico and Oklahoma has ended earlier this year.
Current outbreaks in the United States include 34 cases in South Carolina and one case hitting towns on the Arizona-Utah border that have sickened more than 150 cases since mid-August.
The main question now is whether either is linked to the outbreak in Texas. To lose elimination status, health data must show a continuous series of measles outbreaks for one year.
Dr. Daniel Salas, who leads immunization efforts at the Pan American Health Organization, said international health officials have recommended the United States “strengthen case investigation protocols” because filling data gaps is key to preventing the virus from spreading again.
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 in the United States in more than three decades. Only nine states have not confirmed cases, according to the CDC.
An outbreak also continues in Chihuahua, Mexico, where health officials have confirmed 4,430 cases as of last week and 21 deaths, according to government health data.
Mexican and American officials said the genetic strains of measles circulating in Canada match those found in Texas and Chihuahua. All of these outbreaks affected specific Christian communities of Mennonites who traced their migration through generations from Canada to Mexico to Seminole, Texas.
In August, officials said Mennonite communities in Belize, Argentina, Bolivia, Brazil and Paraguay experienced outbreaks of the same type of measles virus.
Mennonite churches officially discourage vaccination, although more conservative Mennonite communities have historically had low vaccination rates and mistrust of government.
It’s tempting to look at outbreaks in a vacuum, Nuzzo said. But she said many of them are likely linked not only to traveling patients but also to anti-vaccine misinformation.
“It’s not a religious ban in most of these cases,” she said. “Maybe it’s just that people don’t trust the authorities, but they also fall prey to these anti-vaccine influencers who capitalize on fears that some people may have.”
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