With Pennsylvania hardest hit, worst US measles outbreak since 1991 accelerates

27 September 2026facebook iconThe Centers for Disease Control and Prevention (CDC) has recorded 3,659 confirmed measles cases across 47 jurisdictions as of late September. Public health agencies reported 171 new infections over the past seven days. Forty separate outbreaks account for 95 percent of all cases, totaling 3,478 outbreak associated infections. Hospital care has been required for 329 people, about 9 percent of patients. Unvaccinated individuals or those with unknown immunization status comprise 95 percent of all reported cases. Only 17 cases have been imported by international travelers.

Falling vaccination rates are driving this national resurgence. Two-dose MMR coverage among kindergartners dropped to 92.4 percent for the 2025-26 school year, down from 95.2 percent in 2019-20. This decline leaves roughly 280,000 kindergartners without protection against the virus. Preventing community transmission requires a herd-immunity threshold of about 95 percent.

This outbreak marks the worst year for domestic measles transmission since 1991. Between 2000 and 2024, the entire quarter-century following domestic elimination, the United States recorded roughly 4,485 cases. The infections recorded in 2026 already equal 82 percent of that 25-year total. Combined, the 5,948 cases reported in 2025 and 2026 exceed the cumulative total of the preceding quarter-century by about 1,463 infections.

Based on CDC figures, maintaining the year’s average pace of 13.7 cases a day will bring the 2026 national total to roughly 4,980 by December 31. If transmission continues at the pace of the past week, the national total will reach roughly 6,030 cases.

Pennsylvania stands at the center of the national epidemic with 890 confirmed cases, adding 129 infections over seven days. It accounts for 24 percent of the national total, the largest share of any state. Lancaster County health officials have recorded 342 of these cases, mainly in the Amish population. Contrary to the media presentation, the majority of the state’s cases are outside Lancaster County. Hospital care has been required for 124 patients as of mid-September, and state authorities have recorded four measles-associated deaths.

Adults aged 20 and older comprise 38 percent of national cases, but public health scientist Jess Steier writes for CIDRAP that the adult share in Pennsylvania is closer to 70 percent.

This adult transmission chain has produced severe complications for infants. At least six babies in Pennsylvania have been born already infected with congenital measles, and two required admissions to intensive care. The American Academy of Pediatrics published clinical guidance this month because physicians are treating a condition they have never seen. Before mass vaccination, women had childhood immunity by the time they gave birth. These mothers had neither immunity nor the option of vaccination.

Four unvaccinated Pennsylvanians have suffered measles-associated deaths. An 18-year-old Mifflin County resident died of acute disseminated encephalomyelitis, a complication occurring in roughly one measles case in 1,000. A 40-year-old Jefferson County woman with asthma and chronic obstructive pulmonary disease died on September 12 following exposure to a laboratory-confirmed case. Ivan Miller died on August 14 shortly after birth of a lacerated spleen, with measles entered in Part II of his death certificate. Mary Stoltzfus, a six-week-old infant born with a rare genetic disorder, died at home on August 18, and the Lancaster County coroner attributes her death to measles. Both infants were below the age of vaccine eligibility.

On Wednesday, September 23, the Centers for Disease Control and Prevention added a single fatality to its 2026 counter, marked with an asterisk. Pennsylvania health authorities have reported four measles-associated deaths. The single death counted by federal officials involved the 18-year-old Mifflin County resident.

This single entry reflects a criterion change enacted on September 4, requiring National Center for Health Statistics mortality records to code measles as the underlying cause. Health and Human Services Secretary Robert F. Kennedy Jr. confirmed the rule on September 15.

The selection demonstrates how these processes function. Acute disseminated encephalomyelitis is a direct neurological complication of measles with no competing mechanism, placing the virus in Part I of the death certificate by necessity. The three uncounted fatalities each present an alternative factor: a ruptured spleen, a rare genetic disorder, and asthma with chronic obstructive pulmonary disease. Requiring measles to be the sole underlying cause excludes every deceased individual who suffered from a co-existing condition. This rule effectively makes a federal policy of the bogus claim made by Kennedy that measles only kills children who are already ill.

CDC Director Erica Schwartz defended the policy in her first interview as director, saying that when someone with COVID-19 was hit by a bus, “often that was called a Covid-related death.” Schwartz speaks like a right-wing talk-radio host, not a scientist: There has been only one such incident, and the diagnosis was corrected on review.

On Thursday, September 17, Health and Human Services Secretary Robert F. Kennedy Jr. keynoted the annual conference of Children’s Health Defense at the Grand Hyatt in Washington. He received a standing ovation. Andrew Wakefield, who lost his medical license after British regulators found he fabricated the 1998 data linking vaccination to autism, spoke after him.

Kennedy told the audience that HHS is now investigating more than 150 reported post-vaccination adverse events for possible links to particular vaccines, and described a task force reviewing the safety, timing and sequence of childhood vaccination, along with a data project drawing on Medicare, Medicaid, state records and private insurers. He urged the members to be patient with the pace of change inside the government. “President Trump will not allow the government to treat parents who question vaccine orthodoxies as lepers,” he said.

Personnel data compiled by the Public Data Observatory show that the CDC workforce fell from 9,279 employees in March 2025 to 6,683 in May 2026. More than 1,200 employees retired over those fourteen months, while the agency hired only 108 new staff. Only one of eleven center directors from March 2025 remains in position, leaving acting officials to lead most divisions.

Demetre Daskalakis, who led the respiratory disease center until resigning in August 2025, described a “zombified CDC” where “the body’s there, the substance is there, but it’s not acting like how an agency like that should act.” Jonathan Mermin, former director of the HIV and sexually transmitted infections center, compared the staffing losses to losing a third of a city’s firefighters while downtown burns.

These cuts directly impair the response to the current outbreak. The branch working on vaccine-preventable diseases lost its four most experienced laboratory scientists, the team analyzing genetic material to determine whether the United States retains its measles elimination status. Requests from local health departments now take more than ten days to answer rather than less than one day, because the public health grant team shrank from twenty project officers to three.

Political appointees have assumed direct control over operations. Nearly twenty Health and Human Services appointees are now communicating directly with agency staff, replacing two or three political officers. Appointees instructed employees to compile diagnostic codes for every measles case since 2010 to document underlying conditions, reinforcing the same false proposition enforced by the new mortality counting rule.

The agency took $362,000 from the program providing free vaccines to children to fund a contract investigating whether immunizing pregnant women causes autism. Ben Edwards, a Lubbock physician whom Kennedy has praised as an extraordinary healer and who treated children while he was himself infected with measles, was given direct access to senior CDC officials and asked them to look into cod liver oil as a measles treatment, citing references dating to the 1700s.

Meanwhile measles counts continue to climb across the Midwest. Health officials in Ohio have recorded 189 cases, while Kentucky has confirmed 67. Wisconsin health authorities report 171 infections, with Grant, Iowa and Lafayette counties, in the southwestern corner of the state, accounting for 155 of them.

In Minnesota, health officials confirmed a domestically acquired measles infection in an unvaccinated Fillmore County adult on September 16, marking the state’s first case since April. Fillmore County recorded a kindergarten MMR vaccination rate of 83.5 percent for the 2025-26 school year, with 5.5 percent holding non-medical exemptions, putting two-year immunization rates near the bottom of Minnesota counties.

These conditions match those that allowed the Pennsylvania epidemic to expand. The outbreak began in Lancaster County in late April with a handful of infections in a region with low immunization coverage. By late September, Pennsylvania recorded 890 cases.

A functioning federal public health system prevents localized cases from expanding into regional epidemics. Real-time surveillance alerts local health departments to transmission across state lines, allowing federal Epi-Aid teams to deploy before an outbreak spreads. An agency that has lost a third of its workforce cannot deploy teams to stop an outbreak at that stage.