The US has lost its measles elimination status after the virus continued spreading for more than 12 months. The decision was made by an expert panel of the Pan American Health Organization (PAHO), Axios reports.

The decision was the expected outcome of a series of major outbreaks that began in early 2025. According to the latest data from the US Centers for Disease Control and Prevention (CDC), 5,412 confirmed measles cases have been reported nationwide since the start of 2026. By comparison, 2,289 cases were recorded in all of 2025. The last time the number was higher was in 1991, when 9,643 people contracted the disease.

Measles elimination status is defined by the absence of continuous transmission of the same strain of the virus for 12 months. Losing this status means the infection is once again spreading domestically and persisting in certain communities.

Public health experts attribute the rise in cases to growing vaccine distrust, the spread of false claims about vaccine safety and effectiveness by federal officials, including Health Secretary Robert F. Kennedy Jr., and cuts to funding for outbreak prevention and control.

The overwhelming majority of those infected were unvaccinated. Although overall vaccination coverage in the US remains relatively high, more than 95% of the population needs to be vaccinated to maintain herd immunity.

A particularly severe outbreak is underway in Pennsylvania, where more than 1,500 measles cases and six related deaths have been reported. Since early 2025, major outbreaks have also occurred in West Texas, along the Utah-Arizona border, and in South Carolina. The actual number of cases may exceed official figures because of insufficient testing and undetected mild cases.

“We cannot allow people in the US to die of measles in 2026,” the Infectious Diseases Society of America said before the decision was announced.

Richard Besser, president and CEO of the Robert Wood Johnson Foundation and former acting director of the CDC, linked the return of measles to damage to the healthcare system and the spread of false claims about vaccines.

Although most measles cases do not lead to severe outcomes, the virus can suppress the body's immune response, increasing susceptibility to other infections. According to the CDC, about one in five unvaccinated people in the US who contract measles requires hospitalization. In some children, the infection can cause long-term complications, including serious neurological conditions that emerge years later.

Canada and the United Kingdom previously lost their measles elimination status. Although such decisions are largely symbolic, they indicate that the virus has once again become established in certain population groups and continues to circulate.