Short Wave - Vaccinated or not, we’re on the brink of a measles epidemic

Episode Date: September 23, 2026

Measles is making a comeback. Ongoing outbreaks in Pennsylvania, South Carolina, Texas, and Utah have documented hundreds of cases, mostly among unvaccinated people. And while local and federal politicians debate the definitions and impact of those measles-associated deaths, health experts worry that we’re overlooking the real problem: the threat of a full-scale epidemic. Today, we talk to one of those experts – epidemiologist Michael Mina – to figure out who’s most at risk and whether there’s any way for us to turn this epidemic around.Interested in more health and medical news? Email us your question at [e-mail] public media with NPR+ and enjoy perks for over 25 podcasts like this one. This show’s perks include sponsor-free listening. Learn more at plus.npr.org. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Remember the schoolyard rhyme Miss Lucy had a baby? Some people jump rope to it, some people learned a hand clapping game, and there was always this one line. Measel said the doctor, mumps said the nurse, nothing said the lady with the alligator purse. The funny thing is that when I was a kid, measles and mumps weren't super common.

Researchers developed a couple of. combined childhood vaccine for measles, mumps, and rebella in the 70s. It was so effective that measles was declared eliminated in the states in 2000. So most people in the U.S., including me, haven't ever experienced it. But measles is making a comeback. Right now, there are ongoing outbreaks, hundreds of cases, mostly among unvaccinated people, documented in states like South Carolina, Texas, and Utah. In Pennsylvania, where the outbreak is biggest, the state health department has reported 792 cases with four measles-associated deaths.

And that last term, measles-associated deaths, has prompted a lot of conflict between politicians like health secretary Robert F. Kennedy Jr. and Pennsylvania Governor Josh Shapiro. We're trying to figure out, you know, who those deaths were and they actually happen. And we can't figure that. I blame RFK and people like him who have spread misinformation and disinformation. But while all these politicians argue, health experts worry that we're overlooking the real problem. I would say we are very much on the road towards an epidemic. This is Michael Minna. He's been studying measles for the last 15 years. He's an immunologist and epidemiologist, plus the chief medical officer at biotech companies in vivid and Truvian.

We could certainly start to see a greater explosion of measles cases as we move into the future. I think it's very likely that the United States will probably lose its elimination status, you know, towards the end of this year. So today on the show, the measles outbreak, which deaths are caused by measles versus which ones are associated with it. And is there any way for us to turn this epidemic around? I'm Regina Barber, and you're listening to Shorewave, the science podcast from NPR. Okay, Michael, so before we get into this current measles outbreak, can you explain what the measles virus does to our bodies? Yeah, measles is much more than just a fever and a rash. Measles causes a tremendous amount of damage to your immune system.

All sorts of organs that are involved in your immune response are really under attack. Yeah. In fact, you were one of the researchers who discovered something called immune amnesia caused by measles. What is that? Yeah, immunological amnesia, essentially. associated with measles is what I think of as one of the most substantial or consequential effects of getting a measles infection. An individual gets infected with the measles virus. The immune cells in the lungs pull that measles virus into the tissue through the lungs and bring it into what we call the lymphoid

tissue. This is the system in our body where the immune cells live and where they grow and where they're maintained and develop immune memory and protection. Well, the measles, virus has this nasty trick. It gets presented to our memory cells. And instead of getting gobbled up by them or, you know, destroyed by them, it actually starts attacking them. And it starts eating away at our immune memory cells. Just like somebody with amnesia, maybe has to go through a process of relearning whatever it might be that they have forgotten. Immunological amnesia is where a kid or an individual might have spent the last 10 years of their life going through the sicknesses of childhood to build up. the protective immune system so they can live pretty comfortably for the rest of their life. But now you've just erased a lot of that. And what we saw was that a simple measles infection that might look simple on the surface can actually be deleting up to 70% of somebody's entire immunological memory pool, making them at very high risk for other infectious diseases for years. And this isn't just deleting how to fight measles. It's like other things, too. Other kind of

learned behavior against other viruses. Is that correct? That's right. And in fact, we call it the measles paradox now. Yeah. So at the end of a measles infection, you end up with extraordinarily powerful anti-measles protection. But at the expense of having lost potentially tremendous amounts protection against RSV or rhinovirus or coronavirus or e coli and all sorts of things yeah so so this claim that like oh if you get it you'll be stronger you're saying in this specific case you'll be stronger against measles but maybe you're going to be weaker against all this other stuff you got before that's it that's exactly right that's devastating it is devastating we actually what we saw was in the pre-vaccine era when most children were getting measles we found that this process of measles

immune amnesia was linked to about half of all childhood infectious disease deaths against everything else. Oh my gosh. Massive, massive impact. And so when we got rid of measles from the community, we saw these amazing reductions in all-cause mortality from other infectious diseases. Wow, because then they kept their immunity from those things. That's right. It wasn't the vaccine itself. It was the not-geting measles that had this downstream benefit of saying, you get to keep your immune memory, and your protection. So the vaccine is almost like an immune preserving tool as well. Yeah. So there's a lot of different jargon that's been thrown around about this recent outbreak. Last month, for instance, an infant in Lancaster County was declared by the Pennsylvania Department of Health to be a measles associated death.

But the local coroner disagreed and said that the baby died from a ruptured spleen. So let's talk about this specific term. Like what's a measles associated death? Yeah, it's a great question. And I hope we come back to that particular case a little bit because it's a really rare situation. But a measles associated death is usually, it's sort of a, I would say, a looser term than saying measles caused to this death. It is that measles had an association with the death. The way that I like to think about it is if you take a step back and say, would this death have occurred had the individual not gotten measles? So, this is where a lot of the disagreement comes from. Like, how do we use this term? Right. And you wanted to mention, why is this case so interesting? Well, the splenic rupture case, I think, is a really interesting case because it just might be what I would consider the one in a million or the one in 10,000 time when somebody maybe truly did die with measles, but not because of measles. A lot of people would say, well, that sounds nuts.

splenic rupture, the childhood measles, of course it was because of measles, but we can look at the literature and we could look at the whole history of measles in the pre-vaccine era and all of the data we've had of measles cases, including many pregnancies with measles in the past when measles was common. And across all of the body of literature, there isn't a single reported case of a splenic rupture in a newborn as a result of these infections. And so I think we want to avoid trying to make inferences when we don't actually have the data. And I worry that in this case, there was so much momentum to want to drive a causal link that it's really getting outside the balance of what is responsible from a public health perspective. Yeah.

So you're saying that when the death is designated measles association, we don't always know how strong that association is. That's right. And we should qualify it. And if we have uncertainty, we should feel very comfortable saying when we're uncertain. It's sort of like psychology 101. You know, if you're trying to gain trust of somebody, like honesty is the best policy. And I think part of being honest in public health is being really clear about what your uncertainties are along with your certainties. Yeah. So speaking of uncertainties, I just want to briefly talk about the science here because RFK Jr. has suggested that getting the measles, could be beneficial. He said at an Amish State Fair in Pennsylvania that it could be cured by vitamin A and chicken soup. So let's just set the record straight here. Is there a cure for measles? So there is no cure for measles, at least not right now. The cure is to get through the infection and build immunity. Vitamin A is a treatment for measles, specifically in vitamin A deficient kids. So for those individuals, giving them vitamin A supplementation,

before or during a measles infection can be life-saving. So that part, there's a lot of truth there. But I would not call vitamin A a cure for measles. There currently is no antiviral for measles that really beats down the virus enough to cure us of it. Yeah. Let's zoom back out a little bit. There's clear danger for people who are unvaccinated and in these immune-compromised groups. How worried should people be if they are vaccinated with this,

measles outbreak. The measles vaccines work extremely well. We can look, unfortunately, on our own soil today, we can actually say, okay, what do we know from just outbreaks over the last few years? And from those outbreaks, we know that there have been tens of thousands of exposures amongst vaccinated individuals and just a handful of vaccine breakthrough cases. So probably if we had a crystal ball and we could say what is the true efficacy of the vaccine right now across the population, we'd probably say that today, it's something like 99.8% effective to prevent measles. So the good thing for listeners right now, I would say, is that the vaccine protection, if you're healthy, if you're not immune compromised, if you were twice vaccinated, you know,

you really don't have a lot to worry about. But there are lots of people who do have a lot to worry about older individuals, people who are immune compromised, for which there are millions in this country. And for kids that babies that haven't gotten their shot just yet. That's right. Every year, you know, there's millions of children at any given time every year who are not old enough to get the shot. So it means millions of kids are at risk at any point in time in the country. Yeah, let's talk about that. You said earlier that the U.S. might lose its elimination status and that we may be in this epidemic, this measles epidemic right now already. So what would that look like?

What we've seen to date is really isolated outbreaks. But as those isolated outbreaks get larger and larger, as we're seeing in Pennsylvania, and at the same time as we see the under-vaccinated or the susceptible population get larger and larger, those two things start to conjoined. And you might start to see one outbreak over here in Kansas hit up and bump up against a new outbreak over here in Colorado, and all of a sudden you have two outbreaks that are actually becoming one. We saw that in Texas last year, where we saw these outbreaks no longer look so isolated. And that's what happens with something like measles. It's so infectious and so transmissible that as the outbreaks get

large, it's a simple probability. And that's when we start to see a small outbreak turn into what we might think of as an epidemic. Do you think that there's a real chance we possibly could reverse course? Like, is there hope? I think there's kind of two answers to that. On the one hand, we have such a high number of immunized people or of no longer susceptible people in this country. It's not like 30% of the population is susceptible. So on the one hand, we'll see outbreaks. And if they get big enough, they have the opportunity to burn themselves out. That's natural herd immunity. Do we want that? We don't want that. No, because people will be hurt. That's right. That's not the way to hope that our epidemics go away. Do I think that there's a way, though, to prevent that? I don't think that there is at this moment in time. I mean, just to be real, I think everything that's happened in the social discourse, the approaches we took with coronavirus vaccines, the reality is there are very large fractions of the country, potentially massive proportions, you know, who feel very strongly and it has sort of led to extreme.

opinions about whether to get vaccinated, or whether to get children vaccinated. Once you lose trust in something like vaccines or public health, more generally, I think it's very, very hard to gain back. Should we just keep beating the same drum and just hoping that somehow it reverses? No. And should we ridicule and criticize people who don't get vaccines

because they truly don't know when they love their kids? No. We have to think of new approaches to reach consensus, to rebuild trust. It's going to be on us to make sure that we reimagine how we do public health and how we reach people who don't necessarily trust us. It's hard to do, but it's necessary to do, right? Thank you so much, Michael, for coming to speak with us about measles.

Thanks so much for having me. This episode was produced by Hannah Chin and edited by Lauren Gonzalez. Tyler Jones checked the facts, and the clips you heard at the top of the episode were from CNN and NBC 10. Jimmy Keely was the engineer. I'm Regina Barber. Thank you for listening to Shortwave from NPR.