The United States could lose its measles elimination status after 26 years as international health experts review prolonged outbreaks, rising infections and declining childhood vaccination rates. A Pan American Health Organisation (PAHO) expert commission began reviewing the country's status on 10 November, with an announcement expected by 17 November, according to the Washington Post.

The review will determine whether measles has spread continuously within the country for at least 12 months, the threshold for losing elimination status. The US achieved elimination in 2000, meaning domestic transmission had been interrupted, although imported infections could still occur.

Measles Cases Reach 35-Year High

The Centres for Disease Control and Prevention (CDC) recorded 5,182 confirmed measles cases as of 5 November, more than double the 2,289 infections reported throughout 2025. This marks the nation's highest annual total since 1991.

The CDC has identified 43 new outbreaks in 2026, with 96% of infections linked to outbreaks.

The rise has also increased the number of people needing hospital care. CDC figures show 562 measles-related hospitalisations in 2026, including 154 children younger than five, 94 patients aged five to 19 and 313 adults 20 or older. One patient's age was unknown. Overall, roughly 11% of confirmed cases required hospital care.

Among all confirmed patients, 96% were either unvaccinated or had no recorded vaccination status. The CDC does not separate those two groups in its published summary.

The resurgence began with a major outbreak in western Texas in January 2025, followed by infections in Utah, Arizona and other states. Noel Brewer, chairman of the US committee reviewing national measles surveillance, said that publicly available data indicated two transmission chains had lasted longer than a year.

US officials are also presenting evidence to PAHO, including laboratory findings and information on how infections spread between communities.

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Falling Vaccination Rates Leave Children Vulnerable

Declining childhood immunisation rates have increased concerns about measles transmission, particularly in communities with low coverage. CDC figures show that measles, mumps and rubella (MMR) vaccination among kindergarten pupils dropped from 95.2% in 2019-20 to 92.4% in 2025-26.

Roughly 280,000 kindergarten children lacked documentation of completing the recommended vaccination series during the latest school year.

Vaccine exemptions among kindergarten pupils also increased, reaching 4.2% in 2025-26 compared with 3.6% the previous year. A report by NBC News noted an investigation that found that roughly three-quarters of counties with recent kindergarten vaccination data were below the 95% coverage threshold needed for community protection.

Health Secretary Robert F. Kennedy Jr. has repeatedly questioned the combined MMR vaccine, while medical experts have raised concerns about the effects of anti-vaccine messaging on public confidence.

Measles Infections Can Cause Severe Complications

Measles is a highly contagious airborne infection that commonly causes fever, coughing, inflamed eyes and rash. Serious complications include pneumonia and encephalitis, which can cause permanent neurological damage.

Children younger than five face particularly high risks of severe complications. Reuters reported that state health departments recorded 11 measles-related deaths since early 2025, compared with seven deaths included in CDC national figures for 2025 and 2026. Reuters reported that the discrepancy followed the CDC's use of National Center for Health Statistics mortality data rather than state totals.

Despite the possibility of losing elimination status, CDC Director Erica Schwartz said that the agency would continue supporting state outbreak responses and promoting vaccination. Two doses of the MMR vaccine are approximately 97% effective against measles, based on CDC data.

PAHO's review will assess transmission patterns, genetic evidence and surveillance data before determining whether sustained domestic transmission has returned to the US.

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