2 new measles cases reported in Chester County as regional Pennsylvania outbreak grows

From Philly and the Pa. suburbs to South Jersey and Delaware, what would you like WHYY News to cover? Let us know!

Two Chester County residents have tested positive for measles, according to state data released this week.

The new cases are part of a recent spike in infections among Pennsylvanians in the south-central part of the state, where 77 children and adults have contracted the highly contagious viral disease since late April.

The regional outbreak now includes cases in Chester, Berks, Dauphin, Lancaster, Lebanon, Northumberland and York counties.

Chester County health officials had anticipated local measles cases, given the county’s close proximity to Lancaster, a travel destination where more than half of outbreak cases have been reported.

“Especially in the warmer weather,” said Jeanne Franklin, the county’s public health director. “Markets are open and museums are being visited and that’s wonderland. So, it’s absolutely expected, and we have such a long border along Lancaster, we can’t ignore it.”

More adults and children in Pennsylvania, and across the country, are vulnerable to measles infections due to declining vaccination rates. As a result, the number of infections and outbreaks have climbed.

Pennsylvania has recorded a total of 89 measles cases so far in 2026, which include several infections that occurred earlier this year. That’s compared to 16 total cases in all of 2025 and 6 cases in all of 2024, national data shows.

The Chester County Health Department has contact tracing and follow-up protocols in place to help identify others who may have been exposed to measles, and to help those who’ve been infected properly quarantine and monitor symptoms.

The next step, Franklin said, is to increase access to vaccines in communities. Two doses of the measles, mumps and rubella vaccine are 97% effective in preventing measles infection and illness, research shows.

Infants are eligible to get one early dose of the vaccine if they live or are visiting areas with outbreaks.

“Yes, we have it available, but let’s make sure we can get it available in different ways,” Franklin said. “We may consider a pop up, we may consider in-home [services], we may consider expanding our hours in our regular facility. All of that is being researched now, but we want to be thoughtful. What makes sense and what will draw people in?”

County health officials say they’re already seeing people come in for measles shots, for themselves or their children, who had not been previously vaccinated.

“We’ve had plenty of people who chose not to before, come in as families and say, ‘It’s time,’” Franklin said. “It’s fantastic.”

The county is also continuing a campaign on social media with the goal of increasing awareness about measles infections, travel precautions and vaccination options.

Part of that messaging includes thanking people who’ve chosen to vaccinate themselves and commending their action to protect others in the community. The campaign also highlights steps people can take to limit the spread of disease, whether they’re vaccinated or not.

That can involve staying home and isolating if potentially exposed to measles, and participating in county contact tracing, Franklin said.

“If you’re being asked for information because you’ve been exposed, please cooperate so other families have an equal chance to make a decision,” she said. “If another family doesn’t know [about their exposure risk], then they can’t decide whether to change their mind to vaccinate, whether to get tested, etc. And that, to me, just seems unfair.”