Short Wave - Could this nasal spray replace all your vaccines one day?

Episode Date: July 27, 2026

There’s the flu vaccine. The covid shot. The RSV shot… What if all of these—and more—could be combined into one universal vaccine? That’s what immunologist Bali Pulendran is working on in his lab. For this episode in our Tech Camp series, Regina G. Barber talks to him about how far he’s gotten, how far he has to go and why our ancient immune system is the key to it all. Plus they discuss how the vaccine may not be a shot at all—but a needle-free nasal spray. Sources: Mucosal vaccination in mice provides protection from diverse respiratory threatsNon-specific effects of BCG vaccine on viral infectionsInterested in more science of the future? Email us your question at [e-mail] public media with NPR+ and enjoy perks for over 25 podcasts like this one. It includes perks like bonus episodes, early access, archive access, curated playlists and 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. Hey, short waver is Regina Barbara here. And Emily Kwong. And we're back with another episode of Tech Camp, our summer series scouting the technological frontier, tracking down the breakthroughs, experiments and innovations that could change everything. And this episode, M, we're talking to a scientist who's developing a universal vaccine, one vaccine to rule them all. That would be incredible because what we have. have now, of course, is a lot of different vaccines to protect against specific pathogens. Yes, that's right. So in this future, there would be no annual flu and COVID and RSV shots. There

would just be one shot for everything. How is that even possible? Yeah. So Bali palendron and immunologist at Stanford University started seriously thinking about this in the late 2010s when he read a paper about tuberculosis. Okay. So the paper found that people vaccinated against tuberculosis were actually protected from other infections like HPV. Whoa. And the TB shot could boost how effective vaccines were against diseases like the flu and yellow fever, too. And he wondered. Why is a vaccine that's been developed to protect against TB inducing such broad immunity

that is able to fight other kinds of infections? I felt that there has to be some underlying mechanism that would explain this. That sounds like a scientist on the hunt. Yeah. And that led him to an ancient part of our immune system, one that treats all pathogens more or less the same. And using this knowledge, he and his team started making a universal vaccine, which they now have shown can work in mice.

So this new universal vaccine that we've developed really is a radical departure from pathogen-specific vaccines. So today on the show, The Future of Vaccines. Gina talks to Bali about why the key may be in our ancient immunity and why a simple nasal spray may be the answer. And along the way, I get a little help from characters like Cinderella and the Cookie Monster to explain the immune system. You're listening to Shortwave, the science podcast from NPR. Okay, Bali, we're talking today about your ongoing research into whether scientists can develop a universal vaccine that protects against many infections. And the key here is activating a different part of the immune.

system from what, you know, a COVID or a flu vaccine would. What is that part of the immune system? That part of the immune system is called the innate immune system. Think of it as the Cinderella of the immune system. The innate immune system is a neglected part of the immune system. It hasn't received much attention for years. Why? Because really not many labs were studying the innate immune system. But you know, it's the oldest immune system we have in our body. It's ancient. It's billions of years old. Whereas the younger antibody-based or the T-cell-based immune system is only a few hundred million years old. That's still pretty old, but not nearly as old as the innate immune system.

Now, the antibodies and T-cells are incredibly specific. Each antibody can only neutralize or bind one virus or one microbe. Same thing with T-cells. The innate immune system cells such as macrophages or dynritic cells can chew up pretty much anything and everything. They gobble things up. Like cookie monsters. They gobble things like cookie monsters.

They are like cookie monsters. And, you know, they are not very discriminatory in their taste. They don't go for the fine gourmet style of bacteria or virus. They pretty much eat up everything in the refrigerator, any kind of virus, any kind of bacteria, any kind of fungi. That's awesome. Okay, so your team published a paper showing you could do this in mice with a nasal spray. Like, what's in this nasal spray?

There are two components in this nasal spray. One, synthetic molecules that can activate cells of the innate immune system in the nose and in the lung. The other is an antigen. An antigen is a protein. Okay. And these two components were able to activate the innate immune system and that provided not only very broad protection against many different viruses, bacteria and even allergens, but could sustain this protection for three months. And it goes back to this innate immune system, these macrophages in the lung that were supercharged so that they were able to gobble up any kind of. of virus or bacteria that came in through the nose into the lungs and chew them up very, very

quickly and get rid of them. So these mice, like, were protected for three months against what? What kind of things were they exposed to? Influenza, SARS-Co-2, other kinds of coronaviruses, bacteria such as Staphaureus, and some other kinds of respiratory bacteria. and even allergens. I'm just wondering about like future vaccines. If we had a universal vaccine, would this be an annual thing like the flu or like could it be longer?

I could see two broadly different types of application for this universal vaccine. So imagine a scenario where one could give this nasal spray during the winter months. And this would provide protection for about three months, maybe a bit longer, maybe up to six months against flu, respiratory-sensitive virus, COVID, the common cold, so very broad protection. So that's one scenario. What's the other scenario? The other scenario is during pandemic times.

Got it. Let's say it's the year 2030. And let's say we have a new virus that is spreading as quickly as COVID did back in 2020, but causing much more severe disease. We wouldn't have nine months to try and make a vaccine that was highly specific to that virus. And so we'd have to come up with something else. And here's where I think this universal nasal spray, if it's administered broadly across the populations, and the very earliest signals of a pandemic could have a profound impact on curbing the disease as a stop-gap measure until such time as the conventional vaccines are developed,

which could take months, probably longer. And you said this work has been done in mice, and the first step is to show that it could possibly work in humans. But how long are we from that? Like, how long do we have to go to get this to start working in humans? So we are now in the process of fundraising to do a human study to show proof of concept in humans that this vaccine could elicit broad protection. And I'm optimistic. I'm hopeful that we can raise the funds. And what we would need to do is toxicology, meaning you do in rabbits,

you do these experiments and show and have a toxicity profile, and then do a dose escalation study in humans, and then ultimately we do, we immunize humans intranasally with this vaccine and deliberately infect them with influenza under a clinical setting and what's called a control, yeah, and then see if it works or not. And we're about, I'd say, about three to four years away from that. Do you think, just from those tests, but do you see a world where you have a universal vaccine that people are getting, like you said, in the winter months within the next 10 years? Is that a hope? Is it a goal? It's certainly an aspirational dream.

As in all cases, as in all cases, you know, it's a long and torturous road to that. I mean, the safety issue is a major concern. We have to do many, many clinical trials, phase one, phase two, phase three to assess whether these are safe, what are the adverse reactions. But I think what our current study has is a roadmap, an immunology roadmap and proof of concept in mice, that this is possible. It's not just theoretical. It's possible. The question is, how do you translate this safely into humans? So when you imagine a world where there is this universal vaccine, it's become a reality. How do you envision the impact? It's hard to overstate this.

And, you know, I'm very close to it. So I'm not a person who's best qualified. But my hope is that it would have a transformative impact because it would be a radical departure from how Vaccines have been developed over the last 230 years since Edward Jenner. And it's a whole new way of thinking about vaccines. So there's much to go before we come to that stage. As I said, safety is of paramount concern. We have to demonstrate safety rigorously in many human studies. Bali, thank you so much for talking to me about the potential of a universal vaccine.

Thank you so much. That was wonderful to talk with you. Shortwavers, if you like this episode, follow us on the NPR app or wherever you're listening from. This way, you'll never miss a new episode. We promise we'll always deliver you an interesting fact. This episode was produced by Burley McCoy and edited by a showrunner Rebecca Ramirez. It was fact-checked by Tyler Jones and Jimmy Healy was the audio engineer. I'm Regina Barber.

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