Could this nasal spray replace all your vaccines one day?

Summary

Short Wave – Tech Camp: Could This Nasal Spray Replace All Your Vaccines One Day?

Date: July 27, 2026
Hosts: Regina Barber & Emily Kwong
Guest: Dr. Bali Pulendran, Immunologist at Stanford University

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Episode Overview

This episode of Short Wave explores an ambitious new frontier in immunology: the development of a universal vaccine, potentially delivered as a simple nasal spray. Hosts Regina Barber and Emily Kwong speak with Dr. Bali Pulendran, whose research focuses on leveraging the "innate" immune system to provide broad, robust protection against a wide array of infectious diseases — and perhaps even allergens. The discussion blends clear scientific explanations (with a little help from Cookie Monster and Cinderella), humor, and speculative optimism, spotlighting not just the science but its transformative potential for global public health.

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Key Discussion Points & Insights

1. The Universal Vaccine Vision

• Current Vaccine Landscape: Multiple vaccines required for different pathogens (flu, COVID-19, RSV, etc.).
  • [00:43] Emily Kwong: “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?”
• Genesis of the Idea: Dr. Pulendran was inspired by research showing the TB vaccine offered protection beyond TB, sparking the hypothesis that broad immune mechanisms could be harnessed.

2. The Innate Immune System: The “Cinderella” of Immunity

• Innate vs. Adaptive Immunity:
  • The innate immune system is ancient and relatively understudied compared to the adaptable, highly specific “antibody and T cell” side.
  • [03:44] Dr. Pulendran: “Think of it as the Cinderella of the immune system. The innate immune system is a neglected part... It's the oldest immune system we have in our bodies.”
• Mechanism: Innate cells like macrophages indiscriminately “gobble up” invaders — “like Cookie Monsters.”
  • [04:30] Dr. Pulendran: “They gobble things up and they gobble things like cookie monsters. They are like cookie monsters... They pretty much eat up everything in the refrigerator.”

3. The Nasal Spray: Components & Mouse Study Results

• What’s Inside:
  • Synthetic molecules that activate innate immune cells in the nose/lungs
  • An antigen (protein) to stimulate immune response
  • [05:18] Dr. Pulendran: “There are two components... synthetic molecules that activate cells of the innate immune system in the nose and in the lung. The other is an antigen... These two components were able to activate the innate immune system.”
• Protection Span and Range:
  • In mice, three months of broad immune protection against several viruses (influenza, SARS-CoV-2), bacteria (staph aureus), and even allergens.
  • [06:21] Dr. Pulendran: “Influenza, SARS, CoV, 2, other kinds of coronaviruses, bacteria such as staph aureus, and some other kinds of respiratory bacteria, and even allergens.”

4. Potential Applications & Scenarios

• Seasonal Protection:
  • A nasal spray given every winter for 3–6 months of broad coverage against respiratory illnesses.
  • [06:47] Dr. Pulendran: “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.”
• Pandemic Rapid-Response Tool:
  • Fast, population-wide administration as a stopgap during emergent pandemics, buying time for pathogen-specific vaccines.
  • [07:19] Dr. Pulendran: “If it’s administered broadly... at the very earliest signals of a pandemic, could have a profound impact on curbing the disease as a stopgap measure...”

5. Roadmap to Human Use

• What’s Next:
  • Human trials are on the horizon, contingent on funding and safety/toxicology studies.
  • [08:24] Dr. Pulendran: “We are now in the process of fundraising to do a human study... We’re about, I’d say, about three to four years away [from trials].”
• Hurdles:
  • Emphasis on safety, multiple phases of trials, long development process.
  • [09:28] Dr. Pulendran: “It’s certainly an aspirational dream... Safety is a major concern. We have to do many, many clinical trials...”

6. Transformative Potential & The Challenges Ahead

• Immunological Roadmap:
  • Current mouse study provides “proof of concept” that broad innate immune activation can work; now must translate to humans.
• Impact:
  • Potentially radical shift from 230 years of pathogen-specific vaccine development.
  • [10:13] Dr. Pulendran: “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.”

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Notable Quotes

• On innate immunity’s overlooked potential:
  • [03:44] Dr. Pulendran: “The innate immune system is a neglected part... It’s the oldest immune system we have in our bodies. It’s ancient.”
• On mechanism of action, with a touch of humor:
  • [04:30] Dr. Pulendran: “They gobble things up and they gobble things like Cookie Monsters. They are like Cookie Monsters... They pretty much eat up everything in the refrigerator.”
• On what this means for pandemic preparedness:
  • [07:25] Dr. Pulendran: “We wouldn't have nine months to try and make a vaccine... This universal nasal spray... could have a profound impact on curbing the disease as a stopgap measure until... conventional vaccines are developed.”
• On the future and scientific optimism:
  • [09:28] Dr. Pulendran: “It’s certainly an aspirational dream... But I think what our current study has is a roadmap, an immunology roadmap and proof of concept in mice that this is possible.”

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Memorable Moments

• Immune System Analogies:
  • Cinderella (neglected, underappreciated innate immunity) and Cookie Monster (voracious, broad reactivity).
• Visionary Framing:
  • Possibility of a single seasonal vaccination protecting against multiple diseases.
• Pandemic Lessons:
  • The drive to be better prepared and act swiftly when new threats emerge.

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Timestamps for Key Segments

• 00:21–01:41: Introduction to the episode’s theme; genesis of universal vaccine idea
• 03:26–05:08: Interview with Dr. Pulendran; explanation of innate immunity — Cinderella and Cookie Monster analogies
• 05:08–06:37: Nasal spray composition and mouse study results
• 06:37–07:24: Possible applications: seasonal use and pandemic response
• 08:11–09:28: Next steps for human trials and timelines
• 09:28–10:45: Discussion of clinical development challenges, future projections, and transformative potential

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Conclusion

This episode lays out the scientific promise and hurdles behind a universal, nasal spray vaccine that activates the ancient, broad-spectrum innate immune system. While still years from human use, the research marks an “immunological roadmap” toward a vaccine future where universal, rapid, and robust protection could finally be within reach — both for everyday seasonal illness and the next pandemic.

Transcript

[NPR Announcer]

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[NPR Host]

You're listening to Short Wave from NPR.

[Regina Barber]

Hey, Short Wavers. Regina Barber 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, em, we're talking to a scientist who's developing a universal vaccine. One vaccine to rule them all.

[NPR Host]

That would be incredible because what we have now, of course, is a lot of different vaccines to protect against specific pathogens.

[Regina Barber]

Yes, that's right.

[NPR Host]

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?

[Regina Barber]

Yeah. So Bali Palendran, an immunologist at Stanford University, started seriously thinking about this in the late 2000 and tens 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.

[NPR Announcer]

Who.

[Regina Barber]

And the TB shot could boost how effective vaccines were against diseases like the flu and yellow fever, too.

[Bali Palendran]

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.

[NPR Host]

That sounds like a scientist on the hunt. Yeah.

[Regina Barber]

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. Which they now have shown can work in mice.

[Bali Palendran]

So this new universal vaccine that we've developed really is a radical departure from pathogen specific vaccines.

[NPR Host]

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.

[Regina Barber]

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 Short Wave, the science podcast from N. Foreign.

[Sponsor Announcer]

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[Regina Barber]

We're talking today about your ongoing research into whether scientists can develop a universal vaccine that protects against many infections. And here is activating a different part of the immune system from what, you know, Covid or a flu vaccine would. What is that part of the immune system?

[Bali Palendran]

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 bodies. 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 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 dendritic cells can chew up pretty much anything and everything. They gobble things up and 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.

[Regina Barber]

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.

[Bali Palendran]

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. 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 virus or Bacteria that came in through the nose into the lungs and chew them up very, very quickly and get rid of them.

[Regina Barber]

So these mice, like, were protected for three months against what? What kind of things were they exposed to?

[Bali Palendran]

Influenza, SARS, CoV, 2, other kinds of coronaviruses, bacteria such as staph aureus, and some other kinds of respiratory bacteria, and even allergens.

[Regina Barber]

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?

[Bali Palendran]

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 syncytial virus, Covid, the common cold. So very broad protection. So that's one scenario.

[Regina Barber]

What's the other scenario?

[Bali Palendran]

The other scenario is during pandemic times.

[Regina Barber]

Got it.

[Bali Palendran]

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 at the very earliest signals of a pandemic, could have a profound impact on curbing the disease as a stopgap measure until such time as the conventional vaccines are developed, which could take months, probably longer.

[Regina Barber]

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?

[Bali Palendran]

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 in what's called a control, and then see if it works or not. And we're about, I'd say about three to four years away from that.

[Regina Barber]

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 that a goal?

[Bali Palendran]

It's certainly an aspirational dream, as in all cases, as in all cases, it's a long and tortuous 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?

[Regina Barber]

So when you imagine a world where there is this universal vaccine, it's become a reality. How do you envision the impact?

[Bali Palendran]

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.

[Regina Barber]

Bali, thank you so much for talking to me about the potential of a universal vaccine.

[Bali Palendran]

Thank you so much. That was wonderful to talk with you.

[Regina Barber]

Short waivers. If you liked 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 Burleigh McCoy and edited by our 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 Tech Camp from Shortwave, the science podcast from npr. See you tomorrow.

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