A person holds a small vial labeled for measles, mumps, and rubella vaccine with a blue cap, seen against a blurred background.
FILE - Dr. Jessica Early holds a vial of the combination measles, mumps and rubella vaccine at Prisma Health Pediatrics in Greer, S.C., March 18, 2026. (Photo by Mary Conlon/AP Photo)

Although no residents in Allegheny County have yet tested positive, the director of the Health Department is planning for the arrival of an outbreak, as transmission continues to increase across Pennsylvania and deaths mount.

Pennsylvania saw an additional 117 new cases in the past week, according to Dr. Iulia Vann, the department director. That’s an increase from around 100 cases last week. The state has seen 731 cases as of Wednesday, she said, with four deaths reported. 

Although two people were exposed in Allegheny County hospitals by interactions with residents from elsewhere, she said, no one in the county has yet tested positive.

Vann said the department has been preparing for a potential response to transmission in the county, including by looking at supplies of PPE and vaccine, plus scouting locations for pop-up vaccination clinics.

This week, she said, she had a chance to speak to “all superintendents” of schools within the county. She did not specify whether this included leaders of private schools, where Public Source has reported the share of unvaccinated children is higher. She held the meeting, she said, to make “sure that we have all of these pieces lined up, so that way the response can be quick, swift and very clear.”

Individuals who are not vaccinated and are exposed to measles could be required to isolate for 21 days, Vann said. “So it could be a pretty significant amount of time someone has to be quarantined, so that’s why we want to have these discussions with the community,” she said.

The department continues to use its lab resources to help other counties test for measles because of the county’s ability to test samples quickly. This week it tested six such samples.

The department is also monitoring the county’s waste water to try to identify measles. “It’s not perfect, we don’t only rely on it, but do have that tool in our toolbox as well,” Vann said.

The county continues to try to remind people that vaccination is the best protection. Vann said 90% of people exposed to measles who are not vaccinated will be infected, while 97% of the people who have received two doses of the vaccines will not.

Oliver Morrison is the health and environment reporter at Pittsburgh’s Public Source and can be reached at oliver@publicsource.org.

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Oliver Morrison is the health and environment reporter at Pittsburgh’s Public Source, covering the systems and conditions that shape people’s well-being, from health care and pollution to infrastructure...