CDC reports 5,182 US measles cases, highest annual tally since 1991

A death in Wisconsin and a national record

An infant in southwestern Wisconsin died of measles, the state's first such death since 1990, the Wisconsin Department of Health Services said on 5 November. STAT reported that the coroner listed measles as the cause and the department withheld further details to protect the family's privacy. The death was the third reported nationally that week, Ars Technica reported, after a New York child's death on Monday and the death of an unvaccinated person in Jefferson County, Pennsylvania, on Wednesday. Pennsylvania's health department did not release the person's age. The CDC reported 5,182 US measles cases across 47 states and jurisdictions as of 5 November, more than double the 2,289 cases recorded in all of 2025. The CDC's counts lag state tallies. Wisconsin officials said "not everyone who becomes ill seeks medical care or gets tested."

Why 5,182 matters

The US stopped domestic measles transmission in 2000 by holding vaccination rates high.

Coverage has since slipped below the 95% level that prevents sustained spread. MMR coverage among US kindergartners fell from 95.2% in the 2019-20 school year to 92.4% in 2025-26, according to CDC data. Among 4,410 cases reported as of 15 October, 451 people, about 10%, needed hospital treatment. In 96% of illnesses, people were unvaccinated or of unknown status.

Where the outbreaks are

By 5 November, Pennsylvania had reported 1,467 cases this year, the largest US outbreak since measles was declared eliminated in 2000, Ars Technica reported. South Carolina's 997-case outbreak, which ended in April, was the previous record. Pennsylvania had reported 1,078 cases as of 7 October, with 207 hospitalizations and five deaths, all in unvaccinated people, according to Ars Technica. Wisconsin reported 431 cases as of 5 November, all but three in unvaccinated people, with nine hospitalizations, STAT reported. New York had 108 cases this year, up from one in 2023, the Guardian reported. Ohio had 228 cases across 21 counties as of 8 October, a 406% increase on the 45 cases recorded in all of 2025, the Ohio Department of Health reported.

The death count dispute

In all, nine measles deaths have been reported in the US this year, eight confirmed by state officials, Ars Technica reported. The toll includes the Wisconsin infant, a New York child and seven deaths in Pennsylvania, six of them confirmed. The Pennsylvania toll includes the Jefferson County death reported on Wednesday. The CDC reports four. KSL reported, citing Reuters, that Health and Human Services Secretary Robert F. Kennedy Jr. changed the method for counting measles deaths. The CDC's National Center for Health Statistics now confirms measles as an underlying cause on a death certificate. That process can take weeks, and the agency has not explained the review. Local officials generally focus on the underlying cause because it reflects the disease that set the fatal process in motion, Reuters reported.

What happens next

The Pan American Health Organization (PAHO) will review in November whether the US has lost its elimination status. Ars Technica reported that experts widely expect it has.

The CDC said on 13 October it would send more support to Pennsylvania to help investigate the outbreak and strengthen response efforts.