By Deidre McPhillips, CNN
(CNN) — The United States has reported more than 2,000 measles cases this year, federal data shows, a higher annual total than the country has seen in decades.
Ongoing outbreaks — particularly in the upstate region of South Carolina and along the border between Arizona and Utah — continue to add dozens of cases each week, threatening the measles elimination status that the US has held for a quarter-century.
As of December 30, there have been 2,065 confirmed measles cases in the US in 2026, according to data published Wednesday by the US Centers for Disease Control and Prevention. The last time there were more than 2,000 cases reported in one year was in 1992, just a couple years after health leaders updated recommendations to say that children should get two doses of the measles-mumps-rubella (MMR) vaccine instead of just one.
Measles is one of the most contagious diseases known, but the MMR vaccine offers highly effective protection. One dose is 93% effective against measles infection, and two doses are 97% effective, according to the CDC.
However, vaccination rates have been falling for years. Last school year, just 92.5% of incoming kindergarteners had received the MMR vaccine, CDC data shows — below the 95% threshold that public health experts say is necessary to prevent outbreaks.
Measles has been considered eliminated in the US since 2000, meaning no outbreaks or other chains of transmission have lasted longer than a year. But multiple large outbreaks this year may be connected, which puts the elimination status on the line if cases continue to grow through late January.
An outbreak centered in West Texas that started in late January was declared over in mid-August. There were hundreds of related cases across Texas and New Mexico, and three unvaccinated people died: two children and one adult.
In early October, the South Carolina health department confirmed that there was a measles outbreak in the upstate region. That outbreak has spread to nearly 180 cases over the past four months and continues to grow; at least 20 new cases have been reported since Friday, and nearly 300 people are in quarantine because of exposure to a known case.
“We know that a large number of our cases are those who we’ve placed in quarantine because of known exposures,” Dr. Linda Bell, South Carolina’s state epidemiologist, said Tuesday. Measles continues to spread through household transmission, in schools and at churches, she said.
An outbreak on the Utah-Arizona line also continues to grow, with more than 350 cases reported between the two states this year.
In November, the Pan American Health Organization, part of the World Health Organization, determined that Canada had lost its measles elimination status amid a large ongoing outbreak there.
“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 at the time.
But possible genetic links between the Texas outbreak and the ongoing South Carolina outbreak put that status at risk for the US.
“The trajectory that we’re looking at now is that we do anticipate more cases well into January,” Bell said. “What that means for us nationally in terms of how they are defining our designation in this country as having eliminated measles is unclear.”
The-CNN-Wire
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