Short Wave - What to Know About The Measles Outbreak

Episode Date: March 18, 2025

Measles is one of the most contagious infectious diseases known to science – more contagious than Ebola, smallpox or COVID-19. Declining vaccination rates over the past few years, plus a recent outbreak in West Texas, have public health experts concerned. Here's what to know about the science of this virus — plus how to protect against it. For the latest, host Regina G. Barber talks to NPR health correspondent Maria Godoy.Interested in other stories about public health? Tell us what you want to hear about by emailing [e-mail]!Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.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. Hey, short wavers, Regina Barbara here. And in the past few weeks, one of the things that's been all over the news is the measles outbreak. This morning, new numbers show the measles virus spreading like wildfire. There doesn't seem to be any slowdown in the growing measles epidemic. The growing measles outbreak in the southwestern United States claimed a second life this week. Fifteen states across the U.S. are now reporting cases. The numbers continue to grow.

How close to containing this? spread our authorities. What's their plan? This outbreak started in West Texas in January and spread across state borders into New Mexico. As of last Friday, there were nearly 300 confirmed cases reported. That surpasses the total measles infections reported in the U.S. in all of 2024. That number is expected to increase when new numbers are released Tuesday. And there have been cases reported in other states as well, like I've heard of cases as far away as Alaska, Pennsylvania, and Kentucky. Although, just to clarify, Gina, those cases have been tied to international travel and not to the Texas outbreak.

Right. And you're here to help us like make sense of all this. Hey, Maria. Hi, Regina. You're a health and science correspondent for NPR. So I know you've been keeping track of all of this, including the nuances between these like individual cases versus the outbreak in Texas. So what is the difference there? So every year the U.S. reports cases of measles. Even though the disease was declared eliminated here in 2000, that just means there wasn't sustained transmission in the country for at least a 12-month period. Yeah. But, you know, measles is still a big problem globally.

So an unvaccinated person or child who travels to a country where measles is spreading can bring the virus back home. You mentioned Alaska. That was a case where an unvaccinated adult had traveled abroad. And there were also cases in Maryland and Kentucky involving people who were returning from international travel. So reports from a bunch of places around the U.S., but an outbreak is different, right? Right. So that's when the virus starts spreading locally like it's doing now in West Texas and just over the border in New Mexico. And that's what concerns public health officials right now. The outbreak is still pretty much spreading in very remote rural areas where vaccination rates are low. But measles is highly contagious. So if an infected person travels to another community with low vaccination rates, they could potentially seed another outbreak there. So today on the show, what you need to know about measles. We're covering the signs and symptoms of this illness, the ways officials are working to stop it from spreading and what you need to know to stay safe.

I'm Regina Barber. And I'm Maria Godoy. You're listening to Shortwave, the science podcast from NPR. Okay, Maria, to start off, can you tell me about the symptoms of measles? Like, if I were to get an infection, what would that look like? So symptoms generally begin about seven to 14 days after infection. It can start with high fever, cough, runny, nose, red, watery eyes like, like, pain. pink eye. Eventually, you develop a red rash that usually starts on your face and can travel down

your body. That rash is the telltale sign of measles. And here's the really important thing. You can be contagious spreading measles four days before and four days after that rash appears. Yeah. And so we've mentioned that it is very contagious. So how does measles spread? Well, so measles is airborne, right? So you walk into a room, you cough, you know, you talk, you spread infectious particles. They hang there in the air for up to two hours. You leave the room. Somebody else comes in.

They're not vaccinated. An hour later, they could get infected. And when we say it's highly contagious, it's probably the most contagious infectious disease known to mankind. Like more contagious than Ebola, more contagious than polio, more contagious than chickenpox. Wow. It's so contagious. I think this is really worth hammering home.

In an unvaccinated world, every person infected with measles. on average would go on to infect as many as 18 other people. Wow. Yeah. And just for context, when COVID first appeared, the estimate is that for every person infected with COVID, they went on to infect roughly three other people. And we saw how COVID spread. So yeah, it's highly, highly contagious.

Wow. So how do we usually keep it from spreading them? Vaccination. That is the key, right? The measles vaccine is super effective. So one dose is 93% effective, which means 93% of people will have. an immune response. Two doses is 97% effective. And you really need that because the estimates are that you need about 95% of people in a community affected to stop outbreaks from occurring, right? Do you need

high vaccination rates? Once you have an outbreak, you want to go and vaccinate anyone around who is not vaccinated, and then you also need good contact tracing, which means you need the people to be figuring out who was exposed and contacting them right away before they go and expose others and spread this. I mean, I think many of us have heard that some parents are concerned that the vaccine is more dangerous than the virus. Like, what do doctors say to that? The vaccine is highly safe and highly effective. Now, there are side effects like there are with, you know, many vaccines, common ones are things like a sore arm, a fever or a mild rash, but they're far, far, far less dangerous than getting measles itself. You know, before the vaccine, measles was a common childhood disease, but it used to

kill four to five hundred people every year in this country. Wow. And even today, measles can have serious consequences. As many as one in 20 cases result in pneumonia, one in a thousand kids will die or end up with severe brain swelling called encephalitis. And it can also lead to blindness. This sounds horrifying. And I know from the news that there's been two recent deaths, an unvaccinated child and an unvaccinated adult. But Maria, since we're talking about these like long-term effects. I've heard that measles can basically wipe out your immune system's memory. Is that right? Correct. So this is something that happens to some extent in every single measles infection. I talked to Stephen Ellage. He's a researcher at Harvard. And he explained that it's kind

of like your immune system gets amnesia. Not only does your brain have a memory, but your immune system has a memory of all the pathogens. It's encountered in the past. Basically what happens is the measles virus can destroy the cells that retain the memory of how. how to fight pathogens that your body has previously defeated. And the more severe your case of measles is the longer at last, the more of your immune system is destroyed. And this amnesia, like the extent of it can vary widely. His studies of unvaccinated kids who were recovered from measles found that anywhere

from like 11 to 73% of their antibodies had been wiped out after an infection. Wow. And this effect can last two to three years. Right. So, like, how worried should people be about this ongoing outbreak? Yeah. At this point, there's really no need to panic. Vaccination rates are still high enough in most of the country to stop a major deadly outbreak from spreading widely. But if vaccination rates continue to fall as they have been for several years now, experts I've spoken with say in five to ten years, we could be back to the days where measles outbreaks regularly infected thousands of people and killed kids every year. How is the federal government responding to this outbreak specifically? Like what are officials recommend people do? It depends on which officials you're talking about.

The CDC issued an alert recently in response to the measles outbreak, urging people who aren't vaccinated to get vaccinated, especially if you're traveling abroad, and that includes any baby six months and older. Right. And by the way, I should note it's traveling abroad anywhere. But when we're talking about Robert F. Kennedy Jr., the head of the Health and Human Services Department,

his messaging is a little bit more mixed. He wrote an editorial earlier this month that's gotten a lot of attention. He did say that, you know, vaccines are an important tool to keep children safe and create community immunity to protect everyone. But he also kind of focused on some other things that left some public health experts, actually that left every public health expert I've spoken with puzzled. One of the things he said was that good nutrition is the best defense against infectious diseases that's puzzling because the best defense against measles is vaccination. That's what

stops an outbreak. That's what stops the infection. Right. And, you know, Kennedy called vaccination a personal choice. He didn't outright say go get vaccinated. And the other thing is RFK Jr. spent a lot of time talking about treatments like vitamin A. Yeah, what's with vitamin A? Well, okay, so the vitamin A does have a role in the treatment of measles, both the World Health organization and the American Academy of Pediatrics recommend supplementation with two doses of vitamin A for kids who have measles. That's because there are studies done in low and middle-income countries several decades ago now that found that when kids are malnourced and are vitamin A deficient, they can have worse

outcomes, right? So vitamin A supplementation can decrease the risk of death and severe disease with measles. There's also some evidence that even if you're not vitamin A deficient beforehand, measles seems to deplete your vitamin A stores. But here's the thing. Vitamin A cannot prevent measles. That's a piece of misinformation that anti-vaccine promoters have been circulating for years and it's still out there on social media.

Okay. Some of these people wrongly promote the idea that if you give your kids vitamin A supplementation for a long period of time, that can protect them for measles. Like you can forego the vaccine, which is not true. Exactly, exactly. And it's actually dangerous potentially because vitamin A builds up. in your body and it can be toxic to the liver. So how can people then protect themselves?

Get vaccinated if you haven't been already and get your kids vaccinated. You know, parents can talk to their pediatricians about getting younger kids vaccinated early if they're traveling abroad or if they live in an outbreak area. I've talked to doctors in New Mexico and in all parts of the U.S. actually, who are seeing vaccine enthusiasm, you know, where people are at. asking, can I get the shot early for my kid, please, because they're taking this outbreak seriously. If you are an adult who was born after 1957 and were vaccinated before 1968, you may want to get re-vaccinated. Early versions of the measles vaccine weren't as effective.

And, you know, if you're not sure about your vaccination status, you can check your records if you don't have access to those or you just can't find them, there's no harm in getting another shot. Maria Godoy, thank you so much for bringing us this reporting. Oh, it's my pleasure and thanks for having me on, Gina. This episode was produced by Hannah Chin, edited by Jane Greenhalts and our showrunner, Rebecca Ramirez. Tyler Jones checked the facts and Jimmy Keely was the audio engineer. Betz Onovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. News clips used at the beginning of this episode were from Today, Scripts News, PBS News, NewsHour, and CBS. I'm Regina Barber.

Thank you for listening to Shortwave. The Science Podcast from NPR.