The United States has officially surpassed last year's record number of measles infections, marking the highest case count since the disease was declared eliminated in 2000. According to data from the US Centers for Disease Control and Prevention (CDC), the country has recorded 2,318 measles cases in 2026, overtaking the 2,289 cases reported during all of 2025—with five months still remaining in the year. Another report from the end of July puts the figure at 2,371 confirmed infections. The latest milestone makes 2026 the worst year for measles in the US since 1991.
Large outbreaks in South Carolina, Utah, and Arizona have infected hundreds of people, while additional clusters have emerged in several other states. Health authorities in South Carolina, battling the largest measles outbreak in 35 years, say that 997 cases have been recorded, although the exact number may be incomplete.
Federal health officials have long said official totals are often underestimates because some infected people never seek medical care. Dr Varun Shetty, chief epidemiologist for the state of Texas, told The Associated Press: "What we're able to count and report is almost always an underestimate of what actually occurred, because it relies on people being willing to be able to get tested, to share information with healthcare providers and with public health. Sometimes that just doesn't happen."
The growing outbreak makes it increasingly likely that the US could be entering a period in which measles once again becomes a regularly circulating disease, capable of sickening thousands of people each year. International health officials are scheduled to meet in November to decide whether the US and Mexico should lose their measles-free status. The US achieved elimination of local measles transmission in 2000 by maintaining high vaccination rates, but coverage has declined in recent years, falling below the 95% level considered necessary to prevent outbreaks.
Experts say reversing the current trend would require a nationwide effort to increase vaccination rates, but such an undertaking appears unlikely under the US health secretary, Robert F Kennedy Jr, who has a long history of downplaying the importance of immunizations and grossly overstating their risks. The American Academy of Pediatrics, which has sharply criticized the Trump administration's approach to vaccines, described the new record as "an avoidable crisis" that disproportionately hurts children.
In July, Delaware announced its first case of measles in more than a decade. Two days later, officials declared an outbreak, with five known cases. Like other parts of the country, vaccination rates have dropped in Delaware, from 98.5% of kindergartners vaccinated against measles, mumps, and rubella (MMR) in 2016 to 94.1% now. A threshold of about 95% is considered essential for herd immunity to protect those who cannot get vaccinated or who don't mount a good immune reaction—including babies and cancer patients.
"We don't want to be below that threshold. And the lower we get, the more likelihood there is that someone who can't be vaccinated yet—because of their age or because of their immune status—is going to come into contact with someone who has unfortunately contracted measles," said Robert Rosenbaum, Delaware's medical director for emergency medical services and preparedness.
Rosenbaum also noted that attitudes toward vaccines have changed in a couple of different ways. The idea of a link between autism and vaccination, now disproved by multiple studies, proved to be "horrible misinformation" that "created a lot of confusion for people," he said. Some parents also began trying to create their own vaccination schedule out of the belief that children receive too many vaccines—a view frequently espoused by Kennedy.
Dr Shetty emphasized the importance of vaccination: "The measles vaccine is one of the most highly effective vaccines that we've had on the market for decades." However, with vaccination rates declining and misinformation spreading, public health officials face an uphill battle. The situation is particularly concerning for vulnerable groups such as young children and people with fragile immune systems, who are most at risk during outbreaks.
As the US surpasses last year's record and continues to see new cases, the need for increased vaccination and public health action becomes ever more urgent. Whether the country can reverse this trend remains to be seen, but experts agree that without a concerted effort, measles may once again become a regular threat.