Short Wave

How a single flu shot could protect you for decades

11 min
Jun 10, 2026about 1 month ago
Listen to Episode
Summary

Scientists are developing a universal flu vaccine that could protect against all influenza strains for years, eliminating the need for annual shots. Researcher Adolfo García Sastre explains how targeting conserved viral regions rather than variable ones could prevent both seasonal and pandemic flu, but the project faces critical funding gaps that threaten to halt clinical trials.

Insights
  • Universal flu vaccine targets conserved (unchanging) viral regions rather than variable ones, enabling multi-year protection instead of annual vaccination
  • Current flu vaccines miss strains regularly—this year's H3 component had only 30% efficacy due to strain mismatch versus typical 70% efficacy
  • Phase 1 trials showed promising antibody levels, but Phase 2 is stalled due to NIH funding cuts and program discontinuation, risking loss of research materials
  • Proving long-term protection requires 4+ years of follow-up studies, making timeline to market at least 5 years away even with immediate funding
  • Funding barriers are as significant as scientific ones—stability programs and clinical trials require resources beyond current NIH support
Trends
Shift from annual reactive vaccines to conserved-region targeting for durable multi-year immunityNIH funding instability creating gaps in vaccine development pipelines and threatening loss of completed research materialsPandemic preparedness focus on universal vaccines covering 100+ potential pandemic flu strains from animal reservoirsNeed for alternative funding models beyond government grants to advance late-stage vaccine developmentGrowing recognition that vaccine efficacy gaps (30-70%) drive need for fundamentally different immunological approaches
Topics
Universal Flu Vaccine DevelopmentInfluenza Virus Mutation and Strain VariationConserved vs. Variable Viral RegionsVaccine Clinical Trial PhasesNIH Funding and Research Program ContinuityPandemic Influenza PreparednessHemagglutinin Subtypes (H1, H3)Immune Response and Antibody LevelsVaccine Efficacy MeasurementAnimal Reservoir Pandemic RiskVaccine Stability ProgramsMulti-Year Vaccine ProtectionSeasonal vs. Pandemic InfluenzaViral Immunology ResearchPublic Health Surveillance Systems
Companies
Mount Sinai School of Medicine
Adolfo García Sastre's institution where universal flu vaccine research is being conducted
National Institutes of Health (NIH)
Primary funding source for vaccine development; CIVIC program discontinuation halted Phase 2 clinical trials
Centers for Disease Control and Prevention (CDC)
Cited for flu mortality and hospitalization statistics; conducts influenza surveillance for vaccine strain prediction
People
Adolfo García Sastre
Leading researcher developing universal flu vaccine; completed Phase 1 trials targeting conserved viral regions
Regina Barber
Podcast host conducting interview with García Sastre about universal flu vaccine research
Quotes
"This shot that we are working on will protect not only against seasonal influenza, not only of this year, not only against next year and next year and next year this year, but also will prevent pandemic influenza from an animal reservoir."
Adolfo García SastreEarly in episode
"The virus cannot change completely. If not, we will not recognize it as influenza."
Adolfo García SastreMid-episode
"So there are some areas in the virus that we call non-protective. So we need to find the protective areas of the virus that are conserved and protective."
Adolfo García SastreMid-episode explanation
"What's holding up phase two? Money. Mainly money."
Adolfo García SastreLate episode
"If we are not able to put this material that we have right now into humans, then it will be lost. And if we want to, in the future, to do it, we need to start again making this material."
Adolfo García SastreClosing discussion
Full Transcript
This message comes from Avallera. What's it like running a business with Avallera? No thinking about tax and compliance. It's handled. Calculating, filing, validating, accurately and audit defensively. Avallera. Agentech, tax and compliance with confidence. You're listening to Shortwave from NPR. The Centers for Disease Control and Prevention estimates that anywhere from 24,000 to 81,000 people died from the flu during this past flu season. Hundreds of thousands more were hospitalized and millions were infected. And this is a moderate season. In the event of a whole flu pandemic, those numbers could be much higher. There's more than 100 potential pandemic flu viruses that could start the pandemic. That's Adolfo García Sastre, a viral immunologist at the I-CAN School of Medicine at Mount Sinai in New York. He's working on a vaccine that could not only protect people from a pandemic flu virus, but all flu viruses. No more annual flu shots. He calls it a universal flu vaccine. This shot that we are working on will protect not only against seasonal influenza, not only of this year, not only against next year and next year and next year this year, but also will prevent pandemic influenza from an animal reservoir. A vaccine like this hasn't been possible before because the virus that causes the flu, influenza, mutates every year, evading the previous year's vaccine. But he says... The virus cannot change completely. If not, we will not recognize it as influenza. And Adolfo and his team are working on a vaccine that can target all versions of the influenza virus, past, present, and future, if they can find the resources. Today on the show, the science behind a vaccine against all flu's and what scientists need to make it a reality. I'm Regina Barber, and you're listening to Shortwave, the science podcast from NPR. This message comes from Avallera. What does running a business feel like with Avallera's Agentech AI platform for global tax and compliance? No hovering over the submit button, no asking for second opinions, no waking up thinking about a filing, no waiting for something to break, because Avallera's Agentech AI handles it, calculating, filing, validating, accurately, and audit-defensively, automatically. Avallera, Agentech Tax and Compliance with Confidence. This is our class. On This American Life, one thing we like is a good mystery. Sometimes about really big things, but most times, the little mysteries are the best. Our lost and found is currently filled with pants. I don't know, I've never seen this happen. Wait, is this true? This is true. Mysteries of every size, each week. This American Life, wherever you get your podcasts. Okay, Adolfo, what about the flu virus impacts why we need a yearly vaccine? Yeah, so that's because the virus changes every year. And when we are talking about human influenza, we are talking about three viruses right now. Okay. And that's the reason why the vaccine has three components. So there is what they are called the influenza A, influenza B. A comes also in two shapes right now in humans. That are called H1 and H3. And H refers to one of the proteins of the virus, the spike of the virus. Okay. So there is one called hemagglutinin, and that's H1 will be hemagglutinin subtype 1. H3 will be hemagglutinin subtype 3. All these three viruses are circulating in people. Some seasons, they are mainly H3s. Some seasons, they are mainly H1s. Some seasons, they are mainly B, but there is always H1s, H3, and Bs causing infections in humans. So flu A, which comes into H subtypes and then Bs. So we need three components, right? But each one of these viruses change every year. And they do so to avoid pre-existing immunity. And the vaccine tries to cover the strains that are circulating. So we make the vaccine for whatever is going to be circulating this year. And the prediction comes from the surveillance that has been done for influenza and we see what is circulating at any time in the year. And sometimes we miss it for at least one of the components. This year, for example, we miss it for H3s. There was this newest strain that became quickly very, very prevalent. And this one was not very well covered by the H3 component of the vaccine. Still, it provides you some efficacy, but instead of having perhaps an efficacy of 70% prevention from disease, then it goes down to 30% because it's mismatched. Right. So all of this refers to current vaccine strategies, like what we do now. That's based on targeting parts of the viruses that change. But what you're working on is targeting regions that stay the same in the influenza virus in order to make this universal flu vaccine, one that we wouldn't need to get every year. Now, historically, there have been barriers to creating this kind of vaccine. What are they? So there are two types of barriers, the scientific barriers. And the other thing is more about what type of resources you need to put, which is more of an economical reason than a scientific reason. The scientific reason is because influenza has conserved areas. The parts of the influenza virus that doesn't change. They don't change that. Correct. That's what we mean by conserved. But not every conserved area is able to induce an immune response that will be able to protect. So you need to identify these ones that are able to protect. It's like, as you imagine, that flu is a cow. That's a cow. So let's imagine it's a cow. Okay. Already there. So you want to get protection from a cow. You need to target areas in the cow that will prevent damage to you. So perhaps you need to stop or cover the head with foam. Let's say that. And then the cow cannot do damage or the feet. Then even if they kick you, they cannot do damage. But if you cover the tail, well, the cow cannot give you any damage with the tail. Right. So there are some areas in the virus that we call non-protective. So we need to find the protective areas of the virus that are conserved. And protective. Yeah. Okay. And then we need to induce an immune response against these conserved areas by deciding a vaccine that is different from the ones that we have. Because the ones that we have only induce good responses against the variable areas. Variable areas, the parts of the virus that change. Yeah. Which are very good. But they don't protect you against future strains. They don't protect you against pandemic strains. The science hasn't gotten here yet because we haven't been able to find those regions. Well, it took a while. Okay. Took a while. Okay. Now we have some candidates. Okay. We have candidates. And then we have to make a vaccine that will react to these regions that don't change. Yeah. Correct. Okay. So your lab is working on a universal flu vaccine and you just finished phase one trial. What did phase one tell you? So phase one, the main thing that tells you safety. And the second thing that I tell you whether you get the immune response that you think is good for the vaccine. Yeah. Did you? Yeah. Wow. In phase one, we got the indexing of antibodies at levels that we think they will be protective. We have not been able to prove that in humans. But we think that the levels that we achieve, they will be protective. So have you started phase two? Phase two, we have not started. We are being in phase one. What's holding up phase two? Money. Mainly money. Yeah. They are very costly. And there was a NIH program that I was called Civic that was for trying to get improved influenza vaccines. They were part of this program. But this program has been stopped. And right now, it's unclear whether it's going to restart. Was this part of the recent government cuts that happened in the last year? Well, it was not really a cut. But there has been also a lot of slowdown in finances from NIH. So these contracts, they were supposed to at one moment bring clinical trials. But because funding stopped it, and there is no call for new proposals yet. And if a call comes, because it takes time to review and then get funded, there's going to be at least a gap of one year or two years. So what will happen to all your material, all those vaccines in that time? The problem with the vaccines that we are ready to go is that if they are not going, they need to maintain a stability program. And this costs money. Money that we don't have. So we are trying to find partners outside the NIH to finance for at least a stability program, or if not also for some phase two, phase one clinical trials that we still need to do. So I feel that you could make something that could help so many people, but it gets stopped by money. Well, it's frustrating, right? I think the money is there. But it's impossible to manage the program on time to be able to renew it again because of the amount of changes that have been in NIH. It's also the amount of money that has been put into this program already. It's not trivial. And if we are not able to put this material that we have right now into humans, then it will be lost. And if we want to, in the future, to do it, we need to start again making this material. Are you optimistic that there will be this universal flu vaccine like created in your lifetime? In my lifetime, I hope so. But in the next five years, I think it's a big challenge because we want to prove not only that it prevents flu, the year that we give the vaccine, but also prevents flu, the second year, the third year, and the fourth year, right? So just to prove that we have a vaccine that protects for four years requires four years of follow-up. So are you optimistic? I am. I will not be working on it. But who knows? I've also tried not to become depressive at the end. This doesn't move forward, right? At least I really would love if we can prove that this is the way for a flu vaccine. But to me, the discovery process, to me, is very exciting also, whether we can translate it into for the good of humanity even better. But just to find new mechanisms is very rewarding for scientists. Adolfo, thank you so much for talking to us today. OK, good. If you liked this episode, check out our episode on a vaccine trial that could end HIV. We'll put a link in our show notes. This episode was produced by Burley McCoy, edited by a showrunner Rebecca Ramirez and fact-checked by Tyler Jones. The audio engineer was Maggie Luther. I'm Regina Barber. Thank you for listening to Shortwave from NPR. This week on the NPR Politics Podcast, Republicans in Congress passed $70 billion in funding for immigration enforcement, $38 billion to ICE alone. That represents a massive increase with little oversight attached to how the money is spent. We unpack how the move limits the power of Congress and what it could mean for the midterms this week on the NPR Politics Podcast.