Pennsylvania's measles outbreak has crossed 1,000 confirmed cases, state health officials announced Monday, Oct. 5, making it the largest state outbreak in more than three decades.

The state has recorded 1,004 cases across 39 counties, along with 198 hospitalizations and five deaths, according to the Bucks County Beacon, which first reported the milestone. All five people who died were unvaccinated.

The outbreak, which began in April west of Philadelphia, has now spread to more counties than the 38 reported as recently as Sept. 18. It surpasses South Carolina's 997-case outbreak for the largest in any single state in recent history.

Bucks County had no confirmed measles cases as of Sept. 18, the most recent local update available. But local vaccination rates are trending down. The county's overall student MMR (measles, mumps and rubella) vaccination rate averages 95.6%, down from 97.6% during the 2019-2020 school year, according to Central Bucks News. At least 12 Bucks County schools recorded kindergarten MMR rates below 90% in 2024, most of them faith-based private or charter schools, according to a Philadelphia Inquirer analysis.

Bucks County health officials say measles requires between 92% and 95% community vaccination to prevent outbreaks.

Neil Ruland, a Bucks County Health Department spokesman, warned on Sept. 19 that the virus could reach the county because "viruses don't stop at county borders." At the time, the statewide count stood at 767, Ruland told the Bucks County Courier Times. The county's kindergarten MMR rate of 93.7% should provide strong protection, he said, but he urged unvaccinated residents to get the shot.

State and federal officials clash on deaths

A dispute between Gov. Josh Shapiro and federal health officials over how measles deaths are counted has added confusion to the crisis.

Pennsylvania reports five deaths. The U.S. Centers for Disease Control and Prevention (CDC) has confirmed only two on its national dashboard. The gap stems from a change the CDC made Aug. 30, when the agency replaced its death count with an asterisk, according to the Doylestown Observer. A footnote stated the National Center for Health Statistics had no 2026 death records listing measles as the underlying cause.

Unnamed officials told the Doylestown Observer that CDC Director Erica Schwartz removed the deaths at Health Secretary Robert F. Kennedy Jr.'s request, after CDC staff had already accepted Pennsylvania's data. The U.S. Department of Health and Human Services disputed that account.

The CDC later added one death back to its tally on Sept. 23 and a second the following week, according to PhillyBurbs.

One of the five state-reported deaths also remains locally unconfirmed. Lancaster County Coroner Stephen Diamantoni told Central Bucks News on Oct. 1 that his office had not confirmed a fifth death reported by the state.

Among the deaths confirmed by county coroners: a 6-week-old infant in Lancaster County, an 18-year-old from Mifflin County who died of a rare neurological complication, and a 40-year-old woman from Jefferson County who died Sept. 12.

Pennsylvania Secretary of Health Dr. Debra Bogen announced the latter two deaths on Sept. 15. Both were unvaccinated.

Vaccination push and what's ahead

Shapiro said on X on Monday, Oct. 5, that providers administered 53,000 MMR vaccines in September, more than double the average monthly total. He called the disease "preventable" and urged residents to consult a health care provider.

Nationally, the U.S. has recorded nearly 3,900 measles cases in 2026, the worst year since 1991. New York's governor declared a disaster emergency Monday, Oct. 5, expanding who can administer measles vaccines in that state.

International health officials are scheduled to meet in November to determine whether the U.S. has lost its measles-free status, a designation the country earned in 2000.

Residents unsure of their vaccination status can contact their family physician or the Bucks County Health Department.