Global public health authorities are convening this week to decide whether the United States will keep the measles-free status it has maintained since 2000. The Pan American Health Organization (PAHO) called for status reports from all 35 member states in the Americas and has convened a panel of external experts to review the submissions and advise on each country's standing.
The expert panel is meeting behind closed doors in Washington during PAHO's annual session, which runs through November 13. Following those deliberations, PAHO Director Jarbas Barbosa will issue a final decision on the status of each country and notify the relevant national authorities. A PAHO spokesperson said the determinations are expected to be released publicly early next week.
Mexico and Bolivia are also on PAHO's watch list because of prolonged measles outbreaks, the spokesperson added in an email on Tuesday. The review process will take into account epidemiological and laboratory evidence to establish whether measles transmission has continued uninterrupted for 12 months or longer.
Public health specialists have expressed alarm at the possibility the United States could lose its measles-free designation. Helen Bedford, a professor of children's health at University College London who has advised the UK government on vaccination, said the situation is "really concerning" and described the U.S. as having been a model for many immunization programs. "But measles is definitely back in the United States," she said, adding that reversing the trend will require substantial effort and that children are likely to suffer as a result.
Senior U.S. health officials have sought to contextualize the rise in cases. The U.S. Department of Health and Human Services said national vaccination rates declined prior to the current U.S. health secretary taking office. Dr. Erica Schwartz, director at the U.S. Centers for Disease Control and Prevention (CDC), said this week that the CDC is working closely with state health authorities to contain outbreaks, with particular attention on communities where immunization coverage has been low for decades.
Schwartz also said that even if the United States were to lose its measles-free status, the public health response would not change in its key elements. "We're going to be doing the same exact thing that we've been doing today," she said, noting that the response includes "reemphasizing that the number one way to prevent measles is the MMR (combined measles, mumps and rubella) vaccine."
Since President Donald Trump took office for a second term in early 2025, nearly 7,500 U.S. measles cases and 11 deaths have been reported by state and federal health authorities, according to those officials' reporting. Measles is highly contagious and commonly causes symptoms such as high fever and a rash; it can also result in serious long-term health complications and death.
PAHO experts will assess whether transmission in the United States has persisted without interruption for at least 12 months by reviewing the available epidemiological and laboratory data. Noel Brewer, a public health professor at the University of North Carolina and chair of an independent U.S. advisory panel on measles, told PAHO experts on Tuesday that the country faces a major measles problem regardless of the formal status outcome. "Whether or not the U.S. loses its measles elimination status, we have a huge problem with measles," he said. Brewer presented the CDC's measles status report and his group's evaluation of that material to PAHO experts but declined to provide details of the presentation.
Efforts at state and federal levels to control outbreaks have been under way, yet U.S. infections have more than doubled this year compared with 2025. Based on publicly available information, Brewer said the outbreak spanning Arizona and Utah, which began in June 2025 and remains active, likely meets the criteria for prolonged transmission.
PAHO's review comes at a time when other countries have had their measles-elimination status rescinded after international review. Canada, Spain and the United Kingdom recently lost measles-elimination status following evaluations by World Health Organization experts. The United States is no longer a member of the WHO but continues its membership in PAHO.
Tensions over vaccination policy and public messaging have factored into the debate around measles control in the United States. The article's reporting notes that the current U.S. health secretary, Robert F. Kennedy Jr., has for years voiced doubts about the safety of measles vaccines without providing scientific evidence. Public health experts cited in the reporting say his actions to reduce the number of childhood immunizations have heightened vaccine hesitancy and contributed to the nation's highest measles infection rate in more than three decades.
Demetre Daskalakis, a former senior CDC official who resigned after the health secretary took office, warned that a formal loss of measles-free designation would reflect broader weaknesses in the U.S. public health infrastructure. "Measles is the great indicator of where the cracks are in our foundation," he said.
The PAHO review and its eventual decision will determine whether the United States maintains the official status it has held since 2000 or is moved to a different category following evaluation of ongoing measles activity, prolonged transmission in specific outbreaks, and the cumulative epidemiological record submitted by member states.