Pennsylvania's measles outbreak added 66 new cases in a single week, pushing the statewide total to 232 as of Wednesday, Aug. 12, according to Main Line Media News. Montgomery County has three confirmed cases.
That's a 32% jump from the 176 cases we reported Aug. 7, when the state launched its school-level vaccination dashboard. By comparison, only 12 new cases were reported statewide from January through April.
Colonial School District and Wissahickon School District both open Monday, Aug. 31. Under Pennsylvania law, families have five days after the first day of school to show proof of vaccination or a scheduled appointment. After that deadline, unvaccinated students must leave school and cannot return until they've received the shot.
Why the deadline matters
Lancaster County remains the epicenter with 133 cases. Chester County has 23, Lebanon County 20 and York County 12. Montgomery County's three cases are relatively low, but the disease is extraordinarily contagious: about 90% of unimmunized people who have close contact with an infected person will contract measles, according to the Montgomery County Health Department.
The virus spreads through the air from coughs and sneezes and can survive in an airspace for up to two hours after an infected person leaves. People become contagious four days before the rash appears, meaning they can spread measles before they know they're sick.
Of the 232 statewide cases, 38 people have been hospitalized and 35% are children under 18, WTAJ reported. No measles-related deaths have been reported in Pennsylvania.
Immunization rates slipping locally
At least 28 schools in Berks, Chester and Montgomery counties started the 2025-26 school year with measles immunization rates below the 95% threshold needed for herd immunity, according to a Pennsylvania Department of Health database launched July 31. MMR vaccination rates in all three counties have declined about 1 percentage point since 2020, dropping just below that 95% mark overall.
As we reported July 25, Colonial Middle School posted an Oct. 1 immunization deadline for seventh-grade vaccines that conflicts with the state's stricter Aug. 31 requirement. Families should follow the state law deadline.
Where to get vaccinated
Pennsylvania Secretary of Health Dr. Debra Bogen, a pediatrician, said in an Aug. 12 statement that the department has provided more than three times as many MMR vaccinations in Lancaster County this year as in all of 2025.
"So far this year, we provided more than three times as many measles, mumps, and rubella vaccinations in Lancaster County than we did in all of 2025," Bogen said.
Statewide, state health centers have administered more than 1,500 MMR doses in 2026.
Montgomery County residents who are uninsured or underinsured can get a free MMR vaccine at the county health clinic in Norristown (610-278-5145) or Pottstown (610-970-5040, 364 King St.). Pennsylvania's Vaccines for Children Program also provides free vaccines to eligible children; families can call 888-646-6864 or email [email protected]. CVS Pharmacies also carry the MMR vaccine.
The state's measles dashboard at pa.gov/measles is updated Monday, Wednesday and Friday afternoons with county-level case counts and demographic data.
