US Measles Cases Top 4,000 as Pennsylvania Leads Nation in Deaths and Hospitalizations

The United States recorded its highest measles case count in decades this week, and the numbers aren't slowing down.

According to CDC data published October 9, the agency confirmed 4,080 measles cases as of October 8. That's up 193 cases from the prior week's tally of 3,887, a 5.0% week-over-week increase. As Reuters reported, the weekly rate of growth has actually eased slightly from the 6.2% rise recorded the week before, but the cumulative picture is stark: the 2026 total is now 78% above every confirmed case counted across all of 2025.

Children are carrying most of the burden. CDC data show that children and adolescents 19 and younger account for 59% of confirmed cases this year. Among children under 5, roughly one in ten has been hospitalized. In total, 414 people have been hospitalized with measles in 2026, or 10% of all confirmed cases, compared with 244 hospitalizations during all of 2025, according to Reuters. Pennsylvania alone accounts for 1,136 cases and 219 hospitalizations.

Five measles-associated deaths have been confirmed in 2026, all of them in Pennsylvania, state health officials told ABC News. The CDC has formally recognized two of those deaths so far, with the agency noting the number is subject to change as it works with the Council of State and Territorial Epidemiologists to standardize measles death classification across jurisdictions.

The vaccination picture explains a lot. According to CDC figures cited by ABC News, 95% of this year's confirmed cases are in people who are either unvaccinated or whose vaccination status is unknown. Only 2% of cases were in people who received both recommended doses of the measles, mumps, and rubella (MMR) vaccine.

Dr. Peter Chin-Hong, an infectious diseases specialist and associate dean at the University of California, San Francisco, told ABC News that the official case count probably understates the actual spread. He noted that many families with sick children never seek a confirmatory test, meaning the 4,080 figure is almost certainly a floor.

Geographically, the outbreak reaches most of the country. According to the CDC, 47 jurisdictions have reported cases this year, and all but five states have had at least one. Pennsylvania has become the clear epicenter. New York declared a statewide disaster emergency earlier this week after reporting 108 cases through October 3, with 92 of those coming since July 15 alone, Reuters reported.

The spread is overwhelmingly outbreak-driven: 96% of confirmed 2026 cases, or 3,897 of 4,080, are linked to a recognized outbreak. CDC data show 42 separate outbreaks have been reported this year, with cases attributable both to outbreaks that started in 2025 and carried over and to new clusters that ignited in 2026.

Public health officials in Pennsylvania say pop-up vaccination clinics and stepped-up awareness efforts are beginning to push MMR uptake higher in hard-hit communities, but with school-age kids comprising the largest share of cases and winter congregation season ahead, clinicians and epidemiologists watching this outbreak won't be reassured by one week of slightly slower growth.

Sources cited:
- CDC Measles Cases and Outbreaks (updated October 9, 2026) (https://www.cdc.gov/measles/data-research/index.html)
- Contagion Live, Measles Update: October 9, 2026 (https://www.contagionlive.com/view/measles-update-october-9-2026)
- Reuters via SRN News, US measles cases rise to 4,080, CDC says (https://srnnews.com/us-measles-cases-rise-to-4080-cdc-says/)
- ABC News, US surpasses 4,000 measles cases with infections confirmed in 45 states (https://abcnews.com/Health/us-surpasses-4000-measles-cases-infections-confirmed-45/story?id=137125273)
- The Spokesman-Review, Measles cases reach 4,080 for the year, the highest in decades (https://www.spokesman.com/stories/2026/oct/09/measles-cases-reach-4080-for-the-year-the-highest-/)