What to Know About The Measles Outbreak

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 https://www.npr.org/people/1082526815/regina-g-barber talks to NPR health correspondent Maria Godoy https://www.npr.org/people/348777820/maria-godoy. Interested in other stories about public health? Tell us what you want to hear about by emailing [email protected] mailto:[email protected]! 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 http://plus.npr.org/shortwave. See pcm.adswizz.com https://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 https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:22Regina Barber?

  Hey, Short Wavers. Regina Barber here. And in the past few weeks, one of the things that's been all over the news is the measles outbreak.

• 0:29Speaker 02

  This morning, new numbers show the measles virus spreading like wildfire. There doesn't seem to be any slowdown in the growing measles epidemic.

• 0:36Speaker 03

  The growing measles outbreak in the southwestern United States claimed a second life this week. Fifteen states across the US are now reporting cases.

• 0:43Speaker 02

  The numbers continue to grow. How close to containing this spread are authorities? What's their plan?

• 0:50Regina Barber?

  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 US 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.

• 1:15Speaker 04

  Although, just to clarify, Gina, those cases have been tied to international travel and not the Texas outbreak.

• 1:20Regina Barber?

  Right. And you're here to help us, like, make sense of all this. Hey, Maria.

• 1:24Speaker 04

  Hi, Regina.

• 1:25Regina Barber?

  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?

• 1:36Speaker 04

  So every year, the US 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.

• 1:46Regina Barber?

  Yeah.

• 1:47Speaker 04

  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.

• 2:10Regina Barber?

  Reports from a bunch of places around the US, but an outbreak is different, right?

• 2:13Speaker 04

  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.

• 2:40Regina Barber?

  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.

• 2:52Speaker 04

  And I'm Maria Godoy.

• 2:54Regina Barber?

  You're listening to Short Wave, the science podcast from NPR.

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• 4:10Regina Barber?

  Okay, Maria, to like start off, can you tell me about the symptoms of measles? Like if I were to get an infection, what would that look like?

• 4:17Speaker 04

  So, symptoms generally begin about seven to 14 days after infection. It can start with high fever, cough, runny nose, red, watery eyes, like pink eye. Eventually, you develop a red rash that usually starts on your face and can travel down your body.

• 4:32Regina Barber?

  Ooh.

• 4:33Speaker 04

  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.

• 4:44Regina Barber?

  Yeah, and so we've mentioned that it is very contagious. So how does measles spread?

• 4:50Speaker 04

  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.

• 5:19Regina Barber?

  Wow.

• 5:19Speaker 04

  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.

• 5:30Regina Barber?

  Wow.

• 5:30Speaker 04

  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.

• 5:43Regina Barber?

  Wow, so how do we usually keep it from spreading then?

• 5:46Speaker 04

  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.

• 5:57Regina Barber?

  Wow.

• 5:57Speaker 04

  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? 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.

• 6:25Regina Barber?

  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?

• 6:33Speaker 04

  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 400 to 500 people every year in this country.

• 6:55Regina Barber?

  Wow.

• 6:55Speaker 04

  And even today, measles can have serious consequences. As many as 1 in 20 cases result in pneumonia, 1 in 1,000 kids will die or end up with severe brain swelling called encephalitis, and it can also lead to blindness.

• 7:09Regina Barber?

  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?

• 7:25Speaker 04

  Correct. So, this is something that happens to some extent in every single measles infection. I talked to Stephen Elidge, he's a researcher at Harvard, and he explained that it's kind of like your immune system gets amnesia.

• 7:37Speaker 06

  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.

• 7:44Speaker 04

  Basically, what happens is the measles virus can destroy the cells that retain the memory of how to fight pathogens that your body has previously defeated.

• 7:52Speaker 06

  And the more severe your case of measles is, and the longer it lasts, the more of your immune system is destroyed.

• 8:00Speaker 04

  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.

• 8:14Regina Barber?

  Wow.

• 8:15Speaker 04

  And this effect can last 2 to 3 years.

• 8:18Regina Barber?

  Right. So like, how worried should people be about this ongoing outbreak?

• 8:22Speaker 04

  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 10 years, we could be back to the days where measles outbreaks regularly infected thousands of people and killed kids every year.

• 8:47Regina Barber?

  Oof. How is the federal government responding to this outbreak specifically? Like, what are officials recommending people do?

• 8:54Speaker 04

  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.

• 9:07Regina Barber?

  Right.

• 9:07Speaker 04

  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.

• 9:52Speaker 04

  That's what stops the infection.

• 9:54Regina Barber?

  Right.

• 9:54Speaker 04

  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.

• 10:07Regina Barber?

  Yeah, what's with vitamin A?

• 10:09Speaker 04

  Well, OK, 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 were studies done in low and middle income countries several decades ago now that found that when kids are malnourished and are vitamin A- 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.

• 10:50Regina Barber?

  Right.

• 10:50Speaker 04

  That's a piece of misinformation that anti-vaccine promoters have been circulating for years and it's still out there on social media.

• 10:57Regina Barber?

  Okay.

• 10:57Speaker 04

  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 from measles.

• 11:06Regina Barber?

  Like you can forego the vaccine, which is not true.

• 11:08Speaker 04

  Exactly, exactly. And it's actually dangerous potentially because vitamin A builds up in your body and it can be toxic to the liver.

• 11:18Regina Barber?

  So how can people then protect themselves?

• 11:21Speaker 04

  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 US, actually, who are seeing vaccine enthusiasm, you know, where people are 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.

• 11:59Regina Barber?

  Wow.

• 11:59Speaker 04

  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.

• 12:14Regina Barber?

  Maria Godoy, thank you so much for bringing us this reporting.

• 12:17Speaker 04

  Oh, it's my pleasure and thanks for having me on, Gina.

• 12:20Regina Barber?

  This episode was produced by Hannah Chin, edited by Jane Greenhalgh and our showrunner, Rebecca Ramirez. Kyla Jones checked the facts and Jimmy Keely was the audio engineer. Beth Donovan 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, Scripps News, PBS NewsHour and CBS. I'm Regina Barber. Thank you for listening to Short Wave, the science podcast from NPR.

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