Dale Weiser is the clinical services supervisor for the Chester County Health Department. Since August, she's been leading efforts to immunize her county's Amish families against measles in their homes. Weiser poses for a portrait at the Chester County Health Department in West Chester, Pa., on Oct. 28, 2026. Daniel Vasta for NPR hide caption

Daniel Vasta for NPR

Measles spreads incredibly fast. For the last few months, so has Dale Weiser's phone number.

Weiser is the clinical services supervisor for the Chester County Health Department in south-central Pennsylvania. Since August, she's been driving out to Amish homes to vaccinate people against measles. She says it usually starts with a phone call.

"I was at a house, like, at 4:30 in the afternoon, and I had a phone call at 8 the next morning saying, 'hey, I heard you were down the street. Can you come do that at my house?'" she says of a typical request she gets from Amish families.…