Pennsylvania says five of its residents have died of measles this year. The CDC’s national tally lists two. Neither number has moved the other, and the gap between them has become one of the more revealing fights in American public health.

The state’s latest update, dated October 2, counts 977 confirmed cases across 39 counties, with 195 people hospitalized. That is 34 more cases than the Pennsylvania Department of Health had reported just two days earlier. Only four of the cases involved vaccinated people, which is under 1% of the total.

The fifth death

On September 30, the Department of Health told the CDC that a Lancaster County resident who tested positive for measles had died. The person was unvaccinated. The department has said little else, pointing to privacy law and the family’s right to grieve in private.

The details matter, because the death has not been independently confirmed locally. Lancaster County’s coroner told CBS 21 he could not confirm it, and the Philadelphia Inquirer reported that state officials called him but offered no specifics. The state maintains the person lived in the county, though it has not said where the death occurred.

The other four deaths were an unvaccinated 18-year-old in Mifflin County, a 40-year-old woman in Jefferson County, and two infants in Lancaster County. In the Jefferson County case, the coroner confirmed an active measles infection at the time of death, alongside severe asthma and COPD. A coroner also said one of the infants had a rare genetic disorder.

Why the numbers don’t match

Pennsylvania uses the term “measles-associated death.” It covers anyone with confirmed measles who dies within 30 days of symptom onset, unless something unrelated caused the death. The state acknowledges that measles may be present without being the immediate cause. Epidemiologists told Al Jazeera the metric has long been a standard at both the WHO and the CDC.

The federal side has changed how it counts. The CDC now draws its measles death figures from National Center for Health Statistics data rather than from state notifiable-disease reports, and CIDRAP reports that this has caused a substantial delay in confirming Pennsylvania’s deaths. The CDC says it is working with state epidemiologists on a standard definition and that its count may change as reviews finish.

A dispute that has turned political

The disagreement began in August. Pennsylvania announced its first two deaths on August 25, and the CDC said its weekly update would leave them out while it reviewed the circumstances and causes.

Health Secretary Kennedy suggested the first reported deaths may have been “altogether fabricated” by a staffer for Governor Josh Shapiro. Shapiro, for his part, said Kennedy personally directed the CDC not to report them. Kennedy has called that claim false, writing on X: “Governor Shapiro’s claim that I directed CDC to suppress Pennsylvania deaths is false.” He has said the CDC applies its own standard for deaths caused by measles.

On September 16, Pennsylvania Health Secretary Debra Bogen wrote to CDC Director Erica Schwartz that the state had begun requesting Epi-Aid, the CDC’s emergency epidemiological support. In a letter reviewed by Reuters, she wrote: “The CDC’s choice not to publicly recognize the deaths undermines our response.” She said the state would rescind the request if the CDC did not communicate the deaths transparently. Schwartz had earlier said the agency was ready to help once the state formally asked. A department spokesperson says talks with CDC staff continue and nothing is finalized.

The national picture

Pennsylvania’s outbreak, which began in late April, sits inside a much larger one. The CDC’s latest weekly update, as reported by CIDRAP, puts the US total at 3,886 confirmed cases, up 228 in a week and the eighth straight week of triple-digit increases. About 95% of those cases were unvaccinated or of unknown status, and 9% resulted in hospitalization.

The year’s total already exceeds 2025’s 2,289 cases, which was the highest count since 1991. The 4,000 mark could fall as soon as next week.

Within Pennsylvania, the outbreak is concentrated. Lancaster County has 391 cases, Mifflin 117 and Chester 83, and 69% of cases are in adults. Kindergarten MMR coverage in Lancaster County is 85%, compared with 94.5% in Philadelphia. Nationally, kindergarten coverage has slipped from 95.2% in 2019-20 to 92.4% in 2025-26, which leaves about 280,000 kindergartners at risk.

There are signs of a response. Pennsylvania providers gave more than 49,000 MMR doses in August and more than 53,000 in September, roughly double the 25,000 in a typical month. Two doses of the vaccine are 97% effective, according to the department.

What to watch

The immediate question is whether the CDC’s count changes as its reviews finish, and whether a shared definition of a measles death emerges. How the CDC resolves that will shape how severe this outbreak looks to the public.

The longer-term stakes are international. The Pan American Health Organization will review US and Mexico measles-elimination status at its annual meeting in November. PAHO’s statement says the review was moved to harmonize the schedule. It will examine whether transmission has continued for a year from outbreaks that began in January 2025. With cases still climbing every week, the answer may be hard to avoid.

For current figures, the Pennsylvania Department of Health dashboard updates Monday, Wednesday and Friday afternoons, and the CDC updates its national numbers weekly. The figures here reflect data through October 2.