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The U.S. Centers for Disease Control and Prevention had recorded 2,318 measles cases as of Thursday, according to the agency’s update on Friday.
Health Department employees enter the Andrews County Health Department’s measles clinic carrying doses of the measles, mumps and rubella vaccine, on April 8, 2025, in Andrews, Texas. (AP Photo/Annie Rice, File) AP
The number of measles cases in the United States has surpassed the record number in all of 2025, with five more months to go in 2026.
The U.S. Centers for Disease Control and Prevention had recorded 2,318 measles cases as of Thursday, according to the agency’s update on Friday.
The country had 2,289 cases in 2025, the worst year for measles More than three decades. Now, 2026 is easily the worst year in the United States for measles since 1991, with outbreaks in South Carolina, Utah and Arizona leading to hundreds of infections and smaller clusters of cases that broke out in other states.
In November, international health officials will meet to determine whether the United States and Mexico have done so They lost their measles-free status. The United States succeeded in eliminating a local measles outbreak in 2000 by maintaining high vaccination rates, which have declined in recent years to Under 95% coverage necessary to prevent the spread of disease.
Measles cases are not counted
While measles cases in the United States are on the rise, it may be impossible to determine exactly how widespread the disease is. Public health departments and disease researchers have long acknowledged that official statistics are incomplete, because some people get sick and don’t seek treatment — something not unique to measles.
Furthermore, experts say the spread may be greater than known because the virus is one of the most contagious viruses known to medicine and vaccination rates have declined nationwide. National vaccination rates for measles, mumps and rubella – which decreased to 92.5% among kindergartners in the 2024-25 school year, up from 95.2% in 2019-20 — masking lower rates in some communities.
And in Utah, where public health officials battled measles For more than a yearThe virus infected more than 700 people during that period, according to the World Health Organization State Department of Health. Experts relying on mathematical modeling and genetic analyzes suggest the widespread outbreak on the Utah-Arizona border could be three to four times larger than currently known, said Dr. Leisha Nolen, the state epidemiologist.
The picture is murkier in South Carolina, which was The country’s largest outbreak in 35 years. The state Department of Health said the total of 997 is likely an undercount, but it does not know by how much.
The missing number is “impossible to know and may vary during an outbreak,” said Dr. Brannon Traxler, acting director of the state Department of Health.
Data gaps may make it difficult to reliably estimate the true scale of the outbreak. Hospitalization rates can be a good measure, experts say, but measles hospitalization rates are a good measure Not required To be reported in every state.
“If we really had a solid gold standard of the percentage of all cases hospitalized or some measure of their severity, that would be another way to estimate the size of the outbreak that we could see if it’s consistent with these other methods,” said Damon Toth, an applied mathematician at the University of Utah School of Medicine who is working on one of the analyzes of the outbreak in Utah.
Researchers are still analyzing an outbreak in Texas in 2025
In Texas, researchers are still working to estimate the size of the state’s outbreak in 2025, and early results show it may have been twice the size of the 762 known cases.
The low numbers were not surprising, said Remy Pascoe, a mathematical epidemiologist at the University of Colorado Boulder who is working on the analysis. Without an adequate community vaccination rate — 95% according to health experts — “there’s not much you can do about measles once you’ve got it,” he said.
The CDC defines an outbreak as three or more linked cases. By the time three such cases are identified in communities with low vaccination rates and less disease surveillance, “you’ve either missed the previous cases or you’ll have many more,” he added.
Dr. Varun Shetty, Texas’ chief state epidemiologist, said there have been cases where people have tested positive for measles, but health officials have been unable to confirm who was in the person’s home or whether they were sick.
“What we can count and report is almost always an underestimate of what actually happened, because it depends on the willingness of people to be able to get tested, and to share information with health care providers and with public health,” Shetty said. “Sometimes it doesn’t happen.”
The state Department of Health had previously stated this 182 possible cases of measles It has not been confirmed in March 2025 among minors in Gaines County — the epicenter of the outbreak — due to a lack of information. The number of confirmed cases in West Texas County for the entire outbreak is 414.
Shetty expects to continue to see measles cases and even outbreaks because so many people are not protected.
“It is really important, not only for individuals, but also for communities, to have high vaccination coverage,” he said.
The doctor says vaccination is about protecting others
Dr. Mark Roberts, retired director of the Public Health Dynamics Laboratory at the University of Pittsburgh School of Public Health, is most concerned about people he calls “innocent bystanders.”
Research and Measles modeling His team shows that those who can’t get vaccinated — young children, people with weakened immune systems, and those who rarely get strong immunity from the vaccine — bear the brunt of early outbreaks.
Roberts said some people see skipping vaccination as akin to deciding not to wear a seat belt in a car.
“Not vaccinating your child is like saying, ‘I don’t want my car to have brakes,'” he said. “Because you could hit other people. You are not alone in your car. But other people.”
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