Global health experts are meeting in Washington this week to decide whether the United States has lost its official measles-free status, a public health achievement it has held since 2000.
The review is being carried out by an independent panel of the Pan American Health Organization (PAHO), which asked all 35 member states in the Americas to submit measles status reports. The panel is deliberating behind closed doors at its annual meeting, which runs through Friday 13 November. Its recommendation will go to PAHO Director Jarbas Barbosa, who will make the final decision, with the outcome expected to be made public early next week.
The United States is under scrutiny because measles transmission has continued without interruption for more than a year. PAHO defines the re-establishment of endemic transmission as the uninterrupted circulation of the same virus genotype and lineage for 12 months or more in a specific area. For the United States, the analysis period runs from 20 January 2025, when an outbreak began in West Texas. A separate outbreak in Arizona and Utah, which began in June 2025 and is still going, is also likely to meet the threshold, according to public health experts.
The scale of the resurgence is stark. Nearly 7,500 measles cases and 11 deaths have been reported by state and federal health officials since President Donald Trump began his second term in early 2025. The Centers for Disease Control and Prevention (CDC) has counted 5,182 confirmed cases this year alone, the highest annual total since 1991. Infections have more than doubled compared with 2025.
The review also covers Mexico and Bolivia, which are on the watch list because of prolonged outbreaks. Canada, Spain and the United Kingdom have already lost their measles-elimination status after similar reviews. The United States left the World Health Organization but remains a member of PAHO, its Americas branch.
The decision poses a test for the Trump administration and its health secretary, Robert F. Kennedy Jr., who has for years cast doubt, without scientific evidence, on the safety of measles vaccines. Public health experts say his moves to cut the number of recommended childhood immunisations have deepened vaccine hesitancy and fuelled the highest infection rate in more than three decades. The Department of Health and Human Services has said national vaccination rates were already declining before Kennedy took office.
Dr Erica Schwartz, director of the CDC, said this week that the agency works closely with states to contain outbreaks, focusing on communities where immunisation rates have long been low. If the United States loses its status, she said, the agency would keep doing “the same exact thing” it is doing now, “reemphasizing that the number one way to prevent measles is the MMR vaccine”.
Noel Brewer, a public health professor at the University of North Carolina who chairs an independent US advisory panel on measles, presented the CDC’s status report to the PAHO experts on Tuesday. He said that whether or not the country loses its status, “we have a huge problem with measles”.
The outcome has not yet been decided, and the panel’s recommendation is not public. To regain elimination status if it is lost, the United States would first have to interrupt endemic transmission for at least 12 consecutive months, then submit a corrective action plan and show routine immunisation coverage of 95 per cent or higher, alongside strong surveillance and rapid outbreak response.
Sources: Reuters (https://www.reuters.com/legal/litigation/us-faces-loss-measles-free-status-experts-meet-review-2026-11-11/), Pan American Health Organization (https://www.paho.org/en/news/2-3-2026-update-review-measles-elimination-status)
