The United States is on the verge of losing its measles elimination status, a distinction it has held for nearly a quarter-century. 

The warning comes as neighboring Canada officially lost its own measles-free designation this week after failing to control a continuous outbreak for over a year.

The Pan American Health Organization announced on Monday that Canada, which had been declared measles-free for almost three decades, could no longer claim the status. The development also revoked the measles elimination verification for the entire Americas region. Now, health officials warn the United States could be next if its own ongoing outbreak is not contained.

“This is a very unfortunate event,” Dr. William Schaffner, a professor of preventive medicine at Vanderbilt University Medical Center, told ABC News. “It certainly is an embarrassment, and it is a ringing alert that we’ve got to do better.”

America has been battling its own significant measles spread since January. More than 1,600 cases have been confirmed across 41 states this year, according to the Centers for Disease Control and Prevention. An outbreak in Texas was particularly severe, infecting over 700 people and resulting in the tragic deaths of two unvaccinated children. Active case clusters are currently spreading in Arizona, Utah, and South Carolina.

If this nationwide transmission continues, the United States risks forfeiting the “eliminated” status it achieved in 2000.

“We have been flirting with the elimination of measles status because there are pockets of parents across the country that are withholding their children from measles vaccination for reasons that escape me,” Dr. Schaffner said. “This vaccine is extraordinarily safe and extraordinarily effective, and measles is definitely not an illness you would want your child to have.”

Canada’s situation serves as a stark warning. Its outbreak, which began in October 2024, has resulted in more than 5,000 cases, primarily concentrated in under-vaccinated communities in Ontario and Alberta. Health officials attribute the crisis to lagging immunization rates, with some regions reporting that only 68 percent of children under two are vaccinated — well below the 95 percent threshold needed to ensure community protection.

Dr. Jarbas Barbosa, director of PAHO, emphasized the need for a coordinated response. “This loss represents a setback, but it is also reversible,” he said at a news conference, urging governments to improve access to vaccination centers and ensure they are well-stocked.

The Americas region was the first in the world to be declared measles-free in 2016. However, that status was briefly lost in 2018 and 2019 following major outbreaks in Venezuela and Brazil. Both countries managed to regain control, allowing the region to reclaim its status in 2024.

“As a region, we have eliminated measles twice; we can do it a third time,” Dr. Barbosa said.

The MMR (measles, mumps, and rubella) vaccine is highly effective at preventing the dangerous virus, which can lead to severe complications like pneumonia, brain swelling, and death. The CDC reports that two doses are 97 percent effective. Despite its proven safety and efficacy, vaccination rates have been declining in recent years, fueled by misinformation and lack of public health outreach.

In September, a CDC panel voted to remove its recommendation for the combined MMR vaccine for young children, but the separate vaccines will still be recommended for this group. Robert F. Kennedy Jr., President Trump’s Health Secretary, opposes some vaccines, but earlier this year, he instructed the CDC to supply needed MMR vaccines to Texas during a measles outbreak there.

When the initial measles broke out in western Texas, health officials said the infections primarily affected the Mennonite community. But the outbreak is spreading beyond this community, “unfortunately,” said director of public health for the city of Lubbock, Katherine Wells.

“West Texas is where the spread of these cases are right now, and we need to make sure that everybody in West Texas is getting vaccinated and is aware of measles and understands the precautions that we need to take,” she told ABC News.