(CNN) — Canada has lost its measles elimination status amid a large ongoing outbreak of the virus, the Public Health Agency of Canada said Monday.

Canada’s health agency was informed by the Pan American Health Organization, part of the World Health Organization, that it had lost its measles elimination status as viral transmission has continued uninterrupted since October 2024.

Although it has slowed recently, according to the Canadian government, the outbreak is still ongoing, primarily within undervaccinated communities.

“PAHO’s Measles and Rubella Elimination Regional Monitoring and Re-Verification Commission reviewed recent epidemiological and laboratory data, confirming sustained transmission of the same measles virus strain in Canada for a period of more than one year,” officials said in a statement from the Public Health Agency of Canada.

The Re-Verification Commission, or RVC, is an independent body of experts created by the Pan American Health Organization to analyze data and the current measles outbreak situation. The group met at the beginning of November and made its recommendations to the PAHO director, who makes the ultimate decision about Canada’s status.

Canada can re-establish its measles elimination status once transmission of the virus strain associated with the current outbreak is interrupted for at least 12 months, the Public Health Agency of Canada said on its website. The agency said it is working with PAHO and local public health leaders to slow the outbreak.

Canada had been considered measles-free since 1998. A measles vaccine was first approved to be used in Canada in 1963, and various vaccination campaigns were successful. But in more recent years, vaccine hesitancy has grown, and vaccination rates fell below the target of 95% coverage for all recommended childhood vaccines, research shows.

“It’s important to say that all the other 34 countries in the region, they keep their certification as measles-free,” PAHO Director Dr. Jarbas Barbosa said Monday. “This loss represents a setback, of course, but it is also reversible.”

However, with the change in Canada’s status, the Americas region officially loses its measles-free status.

There are no formal consequences to losing such status. But until measles is eliminated worldwide, countries will face the risk of reintroduction and the spread of the virus, Barbosa said. The virus is so contagious that one infected person can transmit the disease to up to 18 others.

As of last month, Canada had tallied more than 5,000 cases for the year — more than twice as many as the country has recorded in the past 25 years combined.

The US has also seen large outbreaks this year and is on the verge of losing its elimination status.

“We are hoping that the US is going to stop the transmission even before that deadline,” said Dr. Daniel Salas, executive manager of PAHO’s Special Program for Comprehensive Immunization.

This year’s large US measles outbreak started in West Texas in January. It’s been declared over, but there is an investigation into whether a growing outbreak along the Arizona-Utah state line could be connected. Cases and outbreaks have also been reported in other states.

“We are supporting all the actions that the US has been taking to actually control the outbreak to stop them,” Salas said.

Mexico also has a recent outbreak, Salas said, concentrated mostly in Chihuahua, but there are also cases in Mexico’s southern states.

“Definitely, they need to continue vaccinating,” Salas said.

With hard work, Barbosa said, he believes that Canada can regain its measles-free status.

“As we have demonstrated before with political commitment regional cooperation and sustain the vaccination, the region can once again interrupt the transmission and reclaim this collective achievement,” Barbosa said.

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