Why Haven't We Cured the Common Cold?

Summary

Chasing Life – “Why Haven’t We Cured the Common Cold?”

Podcast: Chasing Life
Host: CNN Podcasts (Guest Host: Meg Tirrell)
Episode Date: December 12, 2025

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Episode Overview

This episode of Chasing Life investigates one of medicine’s most persistent mysteries: despite decades of research and the enormous economic and human toll, why haven't we found a cure or vaccine for the common cold? Guest host Meg Tirrell interviews leading researchers who have devoted their careers to studying colds, exploring the many scientific and practical challenges that stand between us and a cure. The episode covers both the history of common cold research and the recent advances—and setbacks—in developing treatments and vaccines.

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Key Discussion Points & Insights

1. The Enigma of the Common Cold

• Frequency and Impact

  • The average adult suffers 2–4 colds yearly (children up to 10) [02:29].
  • Annual US economic burden is estimated at $40 billion [02:28].

• Persisting Challenge

  • Dr. Arnold Monto, who has studied colds for 50 years, admits little has changed in how we treat them:

    "Basically, in terms of what we can do for them, it hasn't really changed."
    — Dr. Arnold Monto (01:00)

2. History of Common Cold Research

• Early Research Efforts

  • Post-WWII, the UK established a dedicated Common Cold Research Unit, using “human guinea pigs” to study virus transmission and search for cures [03:09-04:19].

  • Experiments included inoculating volunteers with nasal secretions to confirm causation:

    "They took material from individuals who had common colds that they couldn't identify the cause, and they inoculated them into other people and discovered, yes, we can produce a cold from it."
    — Dr. Arnold Monto (04:00)

• Vaccine and Drug Attempts

  • 1961: Aspirin and hot whiskey were popular cures in absence of real treatments [04:32].
  • 1980s: Interferon nasal spray showed promise, but caused nasal bleeding and wasn't safe for mass use [05:02].
  • 2000s: Placoneirol, an antiviral, failed in final trials due to side effects impacting menstrual cycles—deemed unsafe for wide distribution [05:07-06:04].

3. Scientific and Practical Barriers

• Diversity of Causative Viruses

  • The common cold isn’t a single disease but a collection of symptoms caused by over 200 virus types, most commonly rhinoviruses and coronaviruses [06:32].
  • No single vaccine can cover all, a key reason for slow progress:

    "The problem with the common cold is that many different viruses can cause it. And so far it's proved impossible to make a vaccine which will combat them all."
    — Common Cold Research Unit Narrator (07:49)

• Risk-Benefit Ratio

  • Because colds are self-limiting, any treatment must have minimal side effects:

    "You can't use something which we would against a more severe illness without knowing that it's very safe."
    — Dr. Arnold Monto (06:16)

4. The Rhinovirus: Nature’s Perfect Pathogen

• Why Rhinoviruses Are So Successful

  • Over 180 types; infect quickly, stay localized in the nose.
  • Transmission is optimized—not too severe to force humans into isolation, but causes enough symptoms to facilitate spreading:

    "I often tell students that I think it's the most perfectly adapted human pathogen because it's so fast, it transmits easy. It doesn't cause very severe disease, which is what the virus wants."
    — Dr. Gary McLean (13:35)

• Immunological Evasion

  • The immune system struggles to keep up due to the sheer diversity and rapid mutation of cold viruses [09:42-10:29].

5. Current and Future Research Directions

• Vaccine Development Obstacles

  • Past vaccines tried to use inactivated virus, but failed because of the many strains—efforts abandoned in the 1970s [12:16-13:30].

• Promising Approaches

  • Dr. Gary McLean at Imperial College London is developing a T cell–stimulating vaccine targeting conserved internal rhinovirus proteins:

    "If we were able to, you know, reset immunity in those people and at the same time protect against new rhinovirus infections, that would go a long way towards stopping hospitalizations."
    — Dr. Gary McLean (15:27)

  • Nasal spray delivery is seen as the best method for future cold vaccines, but progress is slow [16:48].

• Who Would Benefit Most?

  • Priority for severe-risk groups: those with COPD, chronic lung diseases, and the elderly [15:27-16:16].

• Timeline and Optimism

  • Dr. McLean's work shows progress in animal models, but a broadly effective, human-ready vaccine is still years away:

    "It's kept incrementally working, each time getting better and better and better. But of course, still far away from covering all of those 180 types of rhinovirus."
    — Dr. Gary McLean (16:35)

6. Expert Strategies for Dealing with Colds (Until There's a Cure)

• Symptom Management Tips
  • Dr. McLean: "I drink lots of water. I will also take vitamin C...try and let it run its course and try not to get dehydrated typically." (17:19)
  • Dr. Monto: "I'll take some antihistamines early...and then do what most people do, and that is suffer and try to stay away from other people." (17:32)
  • Dr. McLean (wryly): "A couple of aspirin and a hot whiskey." (17:57)

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Notable Quotes & Memorable Moments

• On the Enduring Nature of Colds:

  "It's one of those things that everybody gets and everybody knows there's nothing much you can do about it. So it's kind of an interesting story, isn't it?"
  — Dr. Gary McLean (09:13)

• On Scientific Optimism:

  "Will we be able to stop it? I don't know. I hope so. It's not gonna stop me from trying."
  — Dr. Gary McLean (14:17)

• On Vaccine Development:

  "I'm beginning to think you have to have a certain level of optimism to be able to work on the common cold."
  — Meg Tirrell (16:48)

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Timestamps for Key Segments

| Timestamp | Segment / Topic | |-----------|----------------------------------------------------------| | 00:02 | Dr. Monto introduces his decades of research | | 02:28 | Prevalence and economic cost of the common cold | | 03:09 | History: Common Cold Research Unit and early studies | | 05:02 | Failed treatments (Interferon, Placoneirol) | | 06:32 | Why a vaccine is so hard to develop | | 07:49 | Multiple viruses cause the “common cold” | | 09:13 | Dr. McLean on the universality and intractability of colds| | 10:22 | List of viruses causing colds (rhinovirus, etc.) | | 13:35 | The perfection of the rhinovirus as a human pathogen | | 15:27 | Vaccine hopes for high-risk groups | | 16:35 | Incremental progress on T-cell vaccine | | 17:19 | How researchers treat their own colds |

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Conclusion

The episode provides a hopeful but realistic portrait of why the common cold remains uncured: the immense variety of viruses, their rapid mutation, and their unique evolutionary adaptation to human hosts all present scientific hurdles. While incremental progress is being made—especially in T cell–targeted vaccines for high-risk groups—a universal cure or prevention remains a challenge for the future. In the meantime, experts recommend basic symptom management and, above all, patience.

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Tone:
Throughout, the conversation is curious, grounded, and lightly self-deprecating, acknowledging the frustration and humor inherent in still chasing a cure for something so basic after decades of earnest effort.

Transcript

[Meg Tirrell]

How long have you been studying colds?

[Dr. Arnold Monto]

Well, I've been studying colds now for about 50 years.

[Meg Tirrell]

This is Dr. Arnold Monto.

[Dr. Arnold Monto]

I'm professor emeritus, either public health or epidemiology. Whichever one works best for you, they're all real.

[Meg Tirrell]

Yeah, it's important to state that up front. And for more than half century he's been studying colds and other respiratory illnesses. Dr. Monto has been at the University of Michigan. He's credited with discoveries as far back as during the 1968 flu pandemic when he helped further our understanding of herd immunity with the findings that vaccinating school kids could reduce infection in entire communities. So as we get deeper into the Northern hemisphere's cold and flu season, which typically runs from October through May with a peak in the winter months, we asked Dr. After 50 years, how much better have we become at treating the most ubiquitous illness of them all, the common cold?

[Dr. Arnold Monto]

Basically, in terms of what we can do for them, it hasn't really changed.

[Meg Tirrell]

Great. I'm Meg Tirrell, CNN medical correspondent, filling in this week for Dr. Sanjay Gupta to ask the question, why haven't we cured the common cold? And will we ever? This is chasing life.

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[Meg Tirrell]

Average person has two to four colds a year. And more if you're a kid up to 10 on average. And they're not just annoying and uncomfortable. They also cause adults to miss work and kids to miss school, which causes adults to miss work. All this adds up to an estimated $40 billion economic impact each year in the US as of a study published in 2003 co authored by none other.

[Dr. Arnold Monto]

Than Dr. Monto, we always come back to economics.

[Meg Tirrell]

Indeed. But despite that economic burden of colds, we have nothing that prevents them, like a vaccine or that we can take to cure them once we're sick. But it's not for lack of trying.

[Common Cold Research Unit Narrator]

The Ministry of Health Research Unit at Harvard Hospital, Salisbury, has been investigating the common cove and volunteers, human guinea pigs have been living there in pairs for 10 days at a time.

[Meg Tirrell]

In fact, for more than 40 years following World War II, there was an entire Common Cold Research Unit in Salisbury, uk.

[Dr. Arnold Monto]

They were very important. As a matter of fact, they were among the first to identify coronaviruses as a potential cause of the common cold. And the way they did it was very interesting because they had volunteers who came and allowed themselves to be inoculated.

[Meg Tirrell]

In other words, volunteers who came to live at the Common Cold Research Unit were given drops in the nose, essentially made up of snot from other people who had colds. Dr. Monto puts it a little more politely.

[Dr. Arnold Monto]

They took material from individuals who had common colds that they couldn't identify the cause, and they inoculated them into other people and discovered, yes, we can produce a cold from it.

[Meg Tirrell]

Their work focused not just on identifying viruses that cause the common cold, but also on trying to develop antiviral drugs to treat them and vaccines to prevent them. By 1961, though, things were still slow going.

[Dr. Gary McLean]

Until we get a vaccine for the common cold, what would you say is the best cure? Well, I'm convinced that the best cure remains a couple of aspirin and a hot whiskey.

[Meg Tirrell]

Even so, over the years, a few seemingly promising drugs emerged, generating flurries of media reports that the cure for the common cold was near. But they always seemed to encounter a fatal flaw. One in the 1980s was called interferon, and administering it by spraying it up the nose seemed to help against common colds.

[Dr. Arnold Monto]

The problem, it caused nasal bleeding and other symptoms.

[Meg Tirrell]

A couple decades later, a biotech company called Viropharma advanced an antiviral drug called Placoneirol, which also generated excitement. It aimed to work by stopping some of the viruses that cause common colds from being able to replicate.

[Dr. Arnold Monto]

Looked pretty good. And then we were involved in field trials in which we were using the drug in phase three studies. It had gone that far. And these are the pre licensure studies. And it was discovered that women who were on birth control had their periods affected. And the company thought that you could put a warning label on and it would get licensed, but they were dreaming because no agency would license a drug that's going to be used as extensively as one against common colds. And it it died.

[Meg Tirrell]

And that's one of the big hurdles for drugs for disease like the common cold. Though colds can cause a lot of misery. People generally get better on their own. So any medicine they take has to come with really low risks.

[Dr. Arnold Monto]

You've got to be sure that the risk benefit ratio is, is right. In other words, you can't use something which we would against a more severe illness without knowing that it's very safe.

[Meg Tirrell]

The other problem is that the common cold isn't just one virus. In fact, it can be caused by more than 200. The most common are called rhinoviruses, which we'll hear about more in a moment. But also, as Dr. Monto mentioned before, coronaviruses.

[Dr. Arnold Monto]

They are probably the second most common virus type to cause colds. And this is one of the reasons why we were so surprised when coronaviruses showed themselves up to be a potential pandemic back when we had SARS, and then a pandemic in 2020 when it arrived as a real pandemic.

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[Meg Tirrell]

So typically, the coronaviruses we'd seen before SARS1 about two decades ago had been fairly mild, more similar to rhinoviruses, right?

[Dr. Arnold Monto]

Very similar. And you can tell them apart? That's part of the problem.

[Meg Tirrell]

Attempts to develop antiviral drugs typically haven't been able to cover all the kinds of viruses that cause common colds. And it's been a similar problem for vaccines, as this newscaster found on his visit to the Common Cold Research Unit in the.

[Common Cold Research Unit Narrator]

The problem with the common cold is that many different viruses can cause it. And so far it's proved impossible to make a vaccine which will combat them all.

[Meg Tirrell]

But researchers haven't given up, and after the break, we talk with one of them.

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[Dr. Gary McLean]

It's one of those things that everybody gets and everybody knows there's nothing much she can do about it. So it's kind of an interesting story, isn't it?

[Meg Tirrell]

Yeah. And scientifically, I think it's so interesting too, because it's not like we haven't tried exactly.

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[Dr. Gary McLean]

Yeah, we tried and failed a lot.

[Meg Tirrell]

Dr. Gary McLean is one of those researchers still working to try to crack the nut that is the common cold. He's an honorary research fellow at Imperial College in London.

[Dr. Gary McLean]

I'm an immunologist, so I come from the point of view of what is it that our immune systems see when we're attacking a virus? And the common cold is a really interesting one because we're seeing a lot of different things all the time, and it's very, very difficult for the immune system to catch up. So it's one of those pathogens that's an extreme challenge. And from that point of view, it attracted me as an immunologist, trying to understand how we can, you know, make the immune system better, maybe, in a way.

[Meg Tirrell]

And he explains it's not just rhinoviruses and coronaviruses our immune systems have to contend with when it comes to the common cold.

[Dr. Gary McLean]

Traditionally, rsv, rhinovirus, adenovirus coronaviruses, human metapneumoviruses, there's a number of them altogether. All of those can cause common colds, and there's a lot of them. That's why we get colds all the time.

[Meg Tirrell]

And rhinoviruses, it turns out, can be especially sneaky.

[Dr. Gary McLean]

So rhinovirus is a very small virus. It's a very geometric shape. It's a smooth kind of surface of protein that attaches to receptors on cells that are in your upper airways. Now, the first discovery of rhinoviruses was actually done at John Hopkins university in the 1950s. And it was a doctor noticed that a bunch of nurses were all suffering from a very similar upper respiratory tract infection and managed to swab them and isolate the virus, which he called what they called JH virus for John Hopkins, and then it was subsequently change the names to rhinovirus, because that comes from the Greek word Rhino is nose. So it's not like influenza, which can travel deeper into the lungs or even the gut. Rhinovirus tends to stay in the nose. It's very fast. It's its weapon of speed. And as we know, there are a lot of them and they're very dangerous little customers because we're always trying to catch up with our immunity to these viruses.

[Meg Tirrell]

And we heard from Dr. Monto about some of the approaches to trying to develop antiviral drugs to treat common colds over the years. But there was a lot of work to try to make vaccines to prevent them as well.

[Dr. Gary McLean]

The old traditional approach with a new pathogen or a virus such as this was you'd grow as much of it as you could in the lab, and then you take some chemicals to inactivate it so that it becomes non infectious. That end product is still what we call immunogenic, which means if you put it into an animal or a human, it would be recognized and an immune response would be made against it. And, of course, these approaches tended to fail because they didn't fully anticipate the breadth of different strains of rhinovirus. So this was in the, probably the 1970s when those kind of approaches were stopped because it was established that it was just too difficult, technically impossible for us to generate immunity to all of those different rhinovirus strains. And at the same time, it was considered. Well, it's not really a very dangerous virus. It doesn't kill many people. There are other things that are perhaps a little more important to focus vaccine approaches on.

[Meg Tirrell]

And the rhinovirus's humble attributes may be part of what make it such a successful virus.

[Dr. Gary McLean]

I often tell students that I think it's the most perfectly adapted human pathogen because it's so fast, it transmits easy. It doesn't cause very severe disease, which is what the virus wants. Right. Remember, it's a parasite. It needs us to make copies of itself. That's its sole aim. Go to the next person, the next nose. And it does that very, very well.

[Meg Tirrell]

That's the thing about viruses. Like, it's sort of perfect if it can infect you and you can carry it around and it makes you symptomatic enough that you sneeze on other people, but not so symptomatic that you stay home and don't sneeze on other people. So it doesn't want to kill you? It doesn't want to put you in bed?

[Dr. Gary McLean]

Not at all.

[Meg Tirrell]

It wants you to be out.

[Dr. Gary McLean]

It wants you to be out. Yeah. Spreading? Yeah. Yep. And it does that brilliantly. So will we be able to stop it? I don't know. I hope so. It's not gonna stop me from trying.

[Meg Tirrell]

So how's he doing it? Well, one of the biggest challenges is figuring out how to train the immune system to recognize all or a lot of the different strains of rhinovirus out There often vaccines show the immune system the outside pieces of a virus. Think of those infamous spike proteins sticking out of the COVID 19 virus, for example. So that the next time we encounter a virus in the wild, the immune system will say, hey, that's not supposed to be here, and be ready to mount its attack. But it turns out there's a target on the inside of rhinoviruses that seems to be more conserved across different strains. So that's what Dr. Maclean's vaccine focuses on. It aims to stimulate part of our immune system that uses T cells, which can seek out and destroy virally infected cells. The goal, at least to start, is to protect people for whom a common cold might be especially dangerous. Those with chronic lung disease, they have.

[Dr. Gary McLean]

The most severe inflammation that can become life threatening. It's triggered by rhinoviruses, and there's no specific cure for that. If we were able to, you know, reset immunity in those people and at the same time protect against new rhinovirus infections, that would go a long way towards stopping hospitalizations. If that works in copd, then that can be translated into other chronic lung diseases such as asthma, and then also the elderly and those whose immune systems are not as powerful and strong. And then eventually one day, it could be applicable to humans that are generally considered healthy. But it might take a while.

[Meg Tirrell]

How long? Well, for about the last decade, MacLean says he's been working to expand how many different types of rhinoviruses can be covered by his vaccine in animals. It's not yet in human clinical trials, which themselves take years before a vaccine might be licensed for broad use. But he says he's been making progress.

[Dr. Gary McLean]

I'm pleased to say that it's kept incrementally working, each time getting better and better and better. But of course, still far away from covering all of those 180 types of rhinovirus.

[Meg Tirrell]

I'm beginning to think you have to have a certain level of optimism to be able to work on the common cold. And we should note, one thing we heard from all the experts we talked with is that because rhinoviruses target the nose, a nasal spray would likely be the best approach to stopping it. It's been tried with COVID and there is an approved nasal spray flu vacc, but it's not anywhere close yet for rhinoviruses. So until then, we're stuck trying to treat our symptoms. So what do the experts do?

[Dr. Gary McLean]

I drink lots of water. I will also take vitamin C. Apart from that, yeah, nothing really. I just try and let it run its course and try not to get dehydrated typically.

[Dr. Arnold Monto]

I'll take some antihistamines early because some of the original antihistamines, the ones that make you sleepy, have a minor effect and then do what most people do, and that is suffer and try to stay away from other people.

[Meg Tirrell]

And if all else fails, there's always.

[Dr. Gary McLean]

A couple of estrin and the hot whiskey.

[Meg Tirrell]

Okay, maybe not. But I am wishing everyone the best of luck this cold and flu season. Sanjay will be back on Tuesday with the next installment of paging Dr. Gupta. Thanks for listening.

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