Haverford Township students who show up for the first day of school on Monday, Aug. 24, without proof of an MMR vaccination will have five school days to get the shot or be sent home.
That state-mandated deadline lands Saturday, Aug. 29, for Haverford families and Monday, Sept. 14, for Radnor Township School District, which opens Tuesday, Sept. 8. The stakes are sharper than usual. Pennsylvania has confirmed 232 measles cases in 2026, with 66 new infections reported in the seven days ending Wednesday, Aug. 12, according to Mainline Media News. That weekly surge dwarfs the 12 total cases recorded statewide from January through April.
Chester County, which borders Delaware County, has logged 23 cases. None of the 232 people confirmed to have measles statewide were fully vaccinated, according to state data reported by the Times-Tribune. Thirty-eight have been hospitalized. About 35% of cases have been diagnosed in children under 18.
The outbreak is Pennsylvania's worst in three decades. The state recorded 16 measles cases in all of 2025.
What parents need to do
Under state law, families must show proof of MMR vaccination, or proof of a scheduled appointment, within five school days of the first day. Students who miss the deadline cannot return to class until they are vaccinated.
Parents unsure of their child's status can now look up school-level immunization rates on a new state database launched July 31 by the Pennsylvania departments of Health and Education. The interactive tool covers kindergarten, 7th grade and 12th grade data for 2025-2026, searchable by county, school, grade, vaccine type and exemption type. Families can filter by "Delaware County" to find rates at local schools.
Pennsylvania Health Secretary Debra Bogen said Aug. 12 that the state has provided more than three times as many MMR vaccinations in Lancaster County this year as in all of 2025.
Where to get vaccinated
Families who need the shot have several options in Delaware County:
- Delaware County Health Department clinics and mobile unit (Wellness on Wheels): Details at delcopa.gov/health/immunizations
- Pediatricians, local pharmacies and urgent-care centers
- CVS Pharmacies statewide
- Pennsylvania's Vaccines for Children Program provides MMR vaccines to eligible children at no cost. Call 888-646-6864 or email [email protected].
Delaware County Health Department director Lora Siegmann Werner said in late July, when the county launched its back-to-school immunization campaign, that "maintaining high vaccination rates in the county is the most effective way to prevent measles outbreaks from spreading."
Why it matters locally
Measles is so contagious that roughly 90% of unvaccinated people who have close contact with an infected person will contract it. The virus can linger in the air for up to two hours after an infected person leaves a room. Statewide, about half of reporting kindergarten facilities fall below the 95% herd-immunity threshold for measles vaccination, and MMR rates in the tri-county area of Berks, Chester and Montgomery counties have dropped about 1 percentage point since 2020.
The two-dose MMR vaccine is 97% effective at preventing measles. Families with questions can reach the Vaccines for Children hotline at 888-646-6864 before the Aug. 24 start date for Haverford Township or the Sept. 8 opening for Radnor.
