Measles cases in Pa. remain low amid national outbreak, but vaccine hesitancy lays groundwork for spread

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The U.S. hadn’t seen a measles death in a decade until this year, but vaccine hesitancy has helped fuel spread of the highly contagious disease.

This story first appeared in How We Care, a weekly newsletter by Spotlight PA featuring original reporting and perspectives on how we care for one another at all stages of life. Sign up for free here . This year marked the first death from measles in the United States since 2015 — and the second and third too.

Amid a major outbreak in the Southwest, the CDC has confirmed over 700 cases of the highly contagious viral illness since the beginning of 2025, the most in five years. Pennsylvania hasn’t seen any deaths, but nine measles cases have been reported across at least five counties — Bucks, Erie, Lancaster, Montgomery, and Philadelphia — as of last week. To learn more about the illness and how an outbreak would impact Pennsylvania, Spotlight PA spoke with Amesh Adalja .



The doctor and Johns Hopkins professor, who lives near Pittsburgh, is an expert on pandemics and infectious diseases. The following conversation has been edited for clarity and length. Spotlight PA: The United States has seen twice as many measles cases this year than it did all of last year.

What’s causing this? Amesh Adalja: Predominantly, the cause has been a major outbreak in Texas involving a very under-vaccinated population, the Mennonite. That outbreak accounts for the bulk of the cases that we’re seeing in the United States right now. How do you think that we should be responding to this? Both in a broad sense, but also as individuals who might be feeling concerned by this news? There’s no magic to measles.

This is a problem that science and medicine had solved in the 1960s. The way that you extinguish a measles outbreak is by getting a high percentage of the population in a given community vaccinated. So the key message from everyone has to be that those individuals who are not vaccinated against measles — anywhere in this country, but particularly in these outbreak zones — need to get vaccinated.

That’s how we put this to an end. It’s not challenging in the sense that there’s not some specific solution that needs to be created. I want to ask about vaccination here in Pennsylvania.

The kindergarten vaccination rates for measles have been dropping — the rate was 96.4% in the 2019-2020 school year, but as of the 2022-2023 school year, it was 94% . Why are we seeing this drop? The drop is multifactorial.

Some of it had to do with catching up because of disruptions that occurred during COVID-19, and some children fell off of the routine childhood immunization. But also an aspect of it has to be the growing anti-vaccine sentiment that has been increasing over time and really accelerated during COVID-19. That vaccine hesitancy was initially directed against COVID-19 vaccines, but it has basically metastasized and now affects all vaccines.

Child vaccination rates ‘going in the wrong direction’ in the Lehigh Valley. Doctors are concerned Which parts of Pennsylvania would be most vulnerable to the impact of an outbreak if one were to happen? Certain select populations where we know that they have lower than average vaccination rates — which would be, for example, Orthodox Jewish communities, Mennonite, Amish, and related groups where the vaccination rates may be suboptimal as well — those are going to be the most susceptible to the outbreaks occurring. But that’s not always the case.

The cases that we had back in 2024 and 2023 were related to people who voluntarily didn’t vaccinate, and that was in the Philadelphia metro area. What happens is, the virus is gonna spread really efficiently if it finds a population that’s under-vaccinated, and that population is geographically cloistered, like the Mennonites in Gaines County, Texas. Anywhere you see that kind of concentration of low vaccination numbers, that’s going to be a hyper-susceptible area.

It will be kindling. If you think of the virus as kind of a fire, that’s a lot of kindling that’s in one given area. Pennsylvania’s Department of Health doesn’t make all measles cases public , but rather does so in situations where it isn’t able to reasonably identify people who are possibly exposed.

Is this a typical approach? What are the benefits and drawbacks? It’s not as if the numbers aren’t tallied. It’s that they don’t ..

. put a press release out for every case. In general, the more transparency we have, the better it is, and the more situational awareness health care providers have of measles cases in their area, the better.

Because ...

it’s not something that’s part of the everyday experience of physicians. So I think it’s really important that when there is a measles case that it’s announced publicly, and not just kind of added to the number and part of a graph somewhere. Even if it’s a one-off case .

.. I think it’s important that people have awareness, because one of the things that’s fueled vaccine hesitancy is that we sort of live in a luxury of not having to think about measles.

There have been major cuts at the U.S. Department of Health and Human Services, the CDC, the NIH, and then there were also some attempted cuts to federal funding for Pennsylvania health departments that have been put on hold by a judge for now.

Do any of these — or the uncertainty created by them — affect the work of tracking measles cases or providing care? Yes, because a lot of times certain grants that are being given to local and state health departments from the federal government are going to be used for some of their ordinary operational activities. When that funding is not there, they have less resources to be able to respond to these outbreaks, to perform their daily operations. I think it’s important to keep in mind that most local health departments are underfunded and understaffed, and they rely upon some of those federal grants in order to do their core functions.

So when there’s disruptions in that funding or uncertainty about that funding, it does directly impact their ability to perform these activities, which could include contact tracing, it could include press releases, it could include setting up vaccination clinics, diagnostic testing. All of those things that are essential to the response are going to be jeopardized when there’s not a clear source of funding or when that funding is uncertain. What does a measles case look like, and if somebody suspects that they or someone they’re caring for might be infected, what’s the next step? Measles is a respiratory virus, so it will usually begin with what we call the three C’s: that stands for cough, coryza — which is a fancy word for runny nose — and conjunctivitis, which means a red eye.

And then you get that characteristic rash. If someone thinks someone they’re caring for has measles, first of all, as long as they’re vaccinated — the carer, or the person that’s exposed — they’re fine. If they’re not vaccinated or only partially vaccinated, there’s going to be actions to take.

If you suspect someone that you’re around has measles, you should encourage them or arrange for them to get testing to actually confirm that it is measles. That’s the key thing. Obviously, if they’re running into trouble — if they have unremitting fever, they’re very fatigued, they’re short of breath — those are things that are going to require immediate medical attention.

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