US Measles Cases Pass 5,000 for the First Time in 35 Years
Measles cases in the United States have passed 5,000 in a single year for the first time since 1991, according to data released by the Centers for Disease Control and Prevention, as the country faces a review next week of the measles-free status it has held since 2000. The CDC counted 5,182 confirmed cases as of November 5, with 330 new infections in the latest week alone. The total is more than double the 2,289 cases recorded in all of 2025.
The outbreak has fallen hardest on the unvaccinated and on children. The vast majority of infections, 96 per cent, were among people who were unvaccinated or whose vaccination status was unknown, the CDC's data showed. Children and teenagers account for about 59 per cent of confirmed cases: children under five make up 18 per cent, and those aged five to 19 account for 41 per cent. Almost all of the cases, 4,993, were linked to outbreaks, with 43 separate outbreaks recorded across the country. Pennsylvania is the hardest-hit state, with 1,487 cases, followed by South Carolina with 670 and Utah with 536.
The death toll has become a dispute in itself. The CDC has recorded four measles-associated deaths in 2026, while state health authorities have reported at least eight deaths linked to the disease, including very young children. Three of the deaths came in a single week: an infant in Wisconsin, the state's first measles death in more than 35 years; a Pennsylvania resident; and a child in Lewis County, New York. Pennsylvania's Department of Health reported six deaths and 1,487 cases this year. The discrepancy arose after the CDC, under Health Secretary Robert F. Kennedy Jr., switched from state health departments' figures to the National Center for Health Statistics' mortality data to track measles deaths, a change Pennsylvania Governor Josh Shapiro has publicly challenged.
Health officials link the scale of the return to falling vaccination. Coverage among kindergarten children fell from 95.2 per cent in the 2019 to 2020 school year to 92.4 per cent in 2025 to 2026, below the level doctors say is needed to stop the virus spreading in a community. Measles is often the first illness to return when routine childhood vaccination slips, because it spreads so easily: before the vaccine arrived in 1963, measles killed an estimated 400 to 500 people a year in the United States, according to the CDC.
The stakes go beyond this year's case count. Measles was declared eliminated in the United States in 2000, which means the virus no longer spread on its own inside the country year round. The Pan American Health Organization is set to review American transmission data on November 10, and if it finds that one strain of the virus has circulated without a break for 12 months, that status is lost. Losing it would be a formal acknowledgement that a disease the country once defeated has re-established itself.
The CDC has said it is working with the US Council of State and Territorial Epidemiologists to establish a standardised definition for measles deaths, and has urged travellers to verify their immunisation status before international trips. For now, the numbers point in one direction: a preventable disease, driven by gaps in routine vaccination, is spreading through the country's children at a pace not seen in a generation, and the institutions that track it cannot even agree on how many it has killed.