Before a measles patient walks in: lessons from Pennsylvania

Pennsylvania's measles outbreak is testing primary care practices on more than diagnosis. Physicians now need to know who is in the waiting room, which staff members are immune and how fast a suspected case gets reported.

The Pennsylvania Department of Health had confirmed 1,398 measles cases in 44 counties this year as of Oct. 28, including 265 hospitalizations and five measles-associated deaths, according to its measles dashboard. Of those cases, 85 were reported in the previous seven days, and fewer than 1% were in fully vaccinated people.

The outbreak has also become a flash point in a national fight over vaccine policy involving U.S. Health and Human Services (HHS) Secretary Robert F. Kennedy Jr.

Nationally, the Centers for Disease Control and Prevention (CDC) counted 4,588 confirmed cases as of Oct. 22, already double the 2,289 reported in all of 2025. The 43 new outbreaks reported this year are approaching 2025's total of 48, and 96% of this year's cases are outbreak-associated. Of those, 1,384 came from outbreaks that began in 2025 and are still producing cases. For comparison, CDC counted 285 cases and 16 outbreaks in 2024.

Cases have been reported in 47 jurisdictions, including Florida, Illinois, Indiana, Michigan, Missouri, Texas and Wisconsin. CDC counts only confirmed cases and notes that state health departments have the most current figures.

"Measles has been reported to remain infectious in air for up to two hours," according to the CDC's infection control guidance for health care settings.

Where the outbreak stands

Lancaster County accounts for 487 cases, followed by Mifflin (198), Chester (93) and Jefferson (87) counties. As of Oct. 26, the department had found community transmission in 16 counties: Centre, Chester, Clarion, Clearfield, Elk, Franklin, Indiana, Jefferson, Lancaster, Mercer, Mifflin, Snyder, Somerset, Union, Warren and York. Of 176 children younger than 5, 64, or 36%, have been hospitalized, the highest rate of any age group. Adults are not spared: 100 of 537 patients ages 25 to 49 (19%) and 18 of 61 patients 50 and older (30%) have been hospitalized. The fifth death, reported Sept. 30, was an unvaccinated Lancaster County resident, Medical Economics reported. Providers statewide gave 56,631 doses of the measles, mumps and rubella (MMR) vaccine in September and 53,296 in October through Oct. 28, according to the dashboard. A typical month is about 25,000, the department has said.

A political flash point

After Pennsylvania reported the first two U.S. measles-associated deaths of 2026 in August, Kennedy questioned on X whether they were real, writing that the announcement "appears to have been premature," ABC News reported. Pennsylvania Health Secretary Debra Bogen confirmed the deaths, and Gov. Josh Shapiro said there are "real-life consequences to spreading misinformation." CDC now lists three U.S. deaths, based on national mortality data, while Pennsylvania counts five under its own definition.

Kennedy has also urged measles vaccination. On Oct. 15, he attributed the outbreak to people who "went unvaccinated during the COVID pandemic" and said, "I am confident I will bring that outbreak to a quick close," Spectrum News reported. He said a dispute with Shapiro over CDC field assistance had been resolved, and CDC said it would send a disease detective to the state.

An August executive order recommends giving childhood vaccines at separate visits and calls for splitting MMR into single-disease shots, though no standalone versions are sold in the United States, Medical Economics reported. The administration says the changes strengthen parental choice. Infection prevention experts warned that more visits mean more missed doses, Infection Control Today reported.

Recognizing and testing

Measles begins with fever as high as 105 degrees, cough, runny nose and conjunctivitis, according to the CDC's clinical overview. A rash usually appears about 14 days after exposure and spreads from the head down. Patients are contagious from four days before to four days after the rash begins.

CDC advises collecting a nasopharyngeal or throat swab for reverse transcription polymerase chain reaction (RT-PCR) testing and a blood sample for measles IgM antibodies at the first visit. Uncomplicated measles is coded B05.9 in ICD-10-CM.

Reporting and isolation

The state health department asks clinicians to report suspected cases immediately to 877-724-3258 or the local health department; state regulations set an outer limit of 24 hours. The department also posts an identification and testing guide and action steps after an exposure. CDC guidance also applies in physician offices:

• Give patients with possible measles arrival instructions when they call.
• Mask them and separate them from other patients as soon as they arrive.
• Use an airborne infection isolation room if one exists; otherwise, a private room with the door closed while arranging transfer.
• Leave the room empty for up to two hours afterward, and have staff wear N95 or equivalent respirators.

Staff immunity and exposures

CDC accepts documentation of two doses of measles-containing vaccine, a positive IgG blood test, laboratory-confirmed disease or birth before 1957 as evidence of immunity for health care personnel.

Exposed patients without immunity can receive MMR within 72 hours or immune globulin within six days, according to CDC guidance. Immune globulin is a priority for infants younger than 6 months, pregnant women without immunity and severely immunocompromised patients.

"A single case of measles in a health care facility can overwhelm any facility's infection prevention and control resources," Karen M. Jones, MPH, RN, CIC, FAPIC, wrote in Infection Control Today.

Vaccination conversations

The state recommends an early dose for infants 6 to 11 months old in counties with sustained transmission, which does not replace the two routine doses.

Two MMR doses are 97% effective, and national kindergarten MMR coverage fell from 95.2% in 2019-2020 to 92.4% in 2025-2026, Jones wrote, citing CDC data.

What comes next

The Pan American Health Organization's measles elimination commission meets Nov. 10-13 to review 2025 and early 2026 data. The United States has held elimination status since 2000. The commission considers endemic transmission re-established when one viral strain spreads uninterrupted for 12 months or longer.