An international panel is reviewing whether measles has resumed spreading continuously in the United States, which has held elimination status since 2000. The U.S. presented its report Tuesday, Reuters reported. The Pan American Health Organization scheduled the closed meeting for Nov. 10 to 13. It has yet to publish a U.S. decision.
The panel's question is whether the country had a chain of measles transmission that persisted for a year or more. The latest federal count, 5,182 confirmed cases through Nov. 5, shows how widely measles has spread this year. The panel needs additional evidence to tell which infections are part of the same chain.
What elimination means
The United States declared measles eliminated in 2000 after stopping continuous domestic transmission. People can still bring measles into the country after catching it abroad, and an imported case can start an outbreak. If that chain ends and a later introduction starts a separate one, the two outbreaks do not establish a year of continuous spread.
The regional verification commission looks for evidence that a chain involving the same virus lineage continued for at least 12 months. It considers case investigations, laboratory results, vaccination coverage and how well health agencies detect and respond to cases. A genetic match is one part of that assessment. The commission also considers what investigators know about where cases occurred and how they might be linked. PAHO identified Jan. 20, 2025 as the start of the U.S. outbreak period for its assessment.
What the case count can tell us
The CDC's Nov. 6 update counted 5,182 confirmed cases so far in 2026, more than twice the 2,289 it recorded for all of 2025. About 96% were associated with outbreaks, including 1,385 linked to outbreaks that began last year. Those are preliminary counts. An outbreak that spans two calendar years can still last less than 12 months, and cases associated with different outbreaks cannot be added together to establish one continuous chain.
Vaccination coverage helps explain where sustained spread is possible. The CDC estimates that 92.4% of U.S. kindergartners had the required MMR doses in the 2025 to 2026 school year, down from 95.2% in 2019 to 2020. A national average can hide schools or communities with far lower coverage. The CDC also groups people who are unvaccinated and those whose vaccination status is unknown together in its case table, so that figure cannot tell readers how many cases were definitively unvaccinated.
The commission will submit its findings to the PAHO director, who formally communicates the classification. The end of the meeting on Friday does not set a public announcement date. There is a recent precedent: Canada lost its elimination status in November 2025 after the panel found sustained transmission. That also ended the Americas' regional status. The U.S. review concerns the country's own classification.
What families can do now
CDC Director Erica Schwartz told Reuters that the agency would keep working with states to respond to measles if the designation changes. The CDC's current vaccination guidance recommends the first routine measles, mumps and rubella (MMR) dose at 12 to 15 months and the second at ages 4 to 6. The agency estimates that two doses are about 97% effective against measles. Families unsure about vaccination records can check with their healthcare provider or state immunization information system.
The CDC has separate guidance for international travelers, including an early dose for infants ages 6 to 11 months. That early dose is followed by two routine doses after the first birthday. For a possible exposure or a fever and rash that could be measles, call the healthcare provider before going in. Calling ahead lets the clinic arrange care without exposing people in the waiting room. The CDC explains how measles spreads in a short video.
