Pennsylvania measles outbreak exceeds 1,000 cases, five deaths reported

The Pennsylvania Department of Health reported Monday that the state has recorded 1,004 measles cases in 2026, spread across 39 counties. Hospitalizations total at least 198, and five deaths have been linked to the outbreak. Two of the deceased were unvaccinated adults, an 18-year-old and a 40-year-old, while two were infants too young for the measles, mumps, rubella (MMR) vaccine. The fifth fatality involved an unvaccinated resident of Lancaster County, the outbreak’s focal point, which has logged 391 confirmed cases.

Fewer than one percent of the state's cases involve individuals fully vaccinated with two doses of MMR, according to health officials. The Centers for Disease Control and Prevention (CDC) said it had not received a formal request for an epidemiologic assistance (Epi-Aid) from Pennsylvania, but stands ready to deploy staff if needed.

Nationwide, measles cases have topped 3,800 in 2026, the highest level since 1991, with infections confirmed in 45 states and Washington, D.C. The CDC continues to recommend two doses of MMR vaccine—first at 12 to 15 months of age and a second at 4 to 6 years—citing 93% effectiveness after one dose and 97% after two. Infants aged 6 to 11 months in high-risk areas may receive an early third dose.

Vaccination coverage among Pennsylvania kindergartners has slipped to 92.4% for the 2025-2026 school year, down from 95.2% before the COVID-19 pandemic. State health officials have administered more than 8,800 MMR doses this year, with roughly 3,500 given in August and over 2,500 in September.