Pennsylvania measles outbreak spreads, with 55 new cases reported since Wednesday

Pennsylvania’s measles outbreak continues to accelerate, with the state Department of Health reporting 55 new cases since Wednesday, pushing the 2026 tally to 890 confirmed cases across 39 counties, according to its September 25 update reported by Outbreak News Today.

The outbreak has resulted in 173 hospitalisations and four confirmed measles-associated deaths. Fewer than one per cent of cases — just four individuals — occurred in fully vaccinated people, and the department notes that the two-dose MMR vaccine provides 97 per cent lifetime protection.

Pennsylvania remains the nation’s hot spot, with 129 new cases in the past seven days, CIDRAP reported on September 25, citing the state health department. Lancaster County is the hardest hit, with 342 cases; two of the state’s measles deaths were reported there.

Nationally, the CDC recorded 3,659 confirmed measles cases, with 171 new this week. Ninety-five per cent of cases are in unvaccinated people or those with unknown vaccination status, and nine per cent have been hospitalised.

The CDC currently lists only one measles death nationally for the year, despite Pennsylvania reporting four measles-associated deaths. The agency said it is working with the Council of State and Territorial Epidemiologists to develop a standardised definition of deaths due to measles, and warned its figure is subject to change.

Sources: Pennsylvania measles as of September 25 — Outbreak News Today; US measles cases continue to climb, topping 3,600 — CIDRAP