This Cold And Flu Season, Get To Know Your Enemy

16:28 minutes

Design by Daniel Peterschmidt
Design by D Peterschmidt


Ever have the sniffles and wonder, Is this allergies, or have I been besieged by the common cold? Cold and flu season comes around every year, and yet it always seems to vex us. The moment you feel that tickle in the back of your throat, you might start frantically popping zinc lozenges. Or perhaps you rely on an old family remedy: Vicks VapoRub and a dirty sock. The worse we feel, the more likely we are to try anything the internet will recommend.

We don’t yet have a cure for the common cold, but understanding the virus’s tactical maneuvers—like hunkering down in the nose and hiding on doorknobs—might help you fight it better. Yale immunobiologist Akiko Iwasaki joins Diane Pappas, a professor of pediatrics at the University of Virginia, to discuss what science has to teach us about the common cold.

Producer Katie Hiler asked several people what they do when they go toe-to-toe with the common cold.

Images via Shutterstock

Segment Guests

Diane Pappas

Diane Pappas is a professor of Pediatrics at the University of Virginia in Charlottesville, Virginia.

Akiko Iwasaki

Akiko Iwasaki is a professor of Immunobiology at the Yale Medical School in New Haven, Connecticut.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. We’re talking about the common cold this hour. It is a perennial invader, which means we’re given plenty of chances to either put up a fight or decide we’re just going to surrender to the sniffles. So what have years of battling the cold virus taught us about how to tackle it? Producer Katie Hiler asked people out here on the streets of New York what they do when they go toe to toe with the common cold.

SPEAKER 1: We think of something natural, you know, like ginger with lime. And we just drink something like a tea.

SPEAKER 2: Ginger tea. Little bit of honey.

SPEAKER 3: I drink a lot of tea. I drink a whole lot of Emergen-C and Airborne.

SPEAKER 4: I’ll tell you what I don’t believe in– Emergen-C. I think that stuff is–

SPEAKER 5: I do believe in Emergen-C.

SPEAKER 4: I think that stuff’s crap.

SPEAKER 5: That’s more preventative, when I’m starting to feel it a little bit.

SPEAKER 4: Emergen-C is absolute nonsense.

SPEAKER 6: Chug a ton of water all day and try to get a good night’s sleep.

SPEAKER 7: Eat some soup– like chicken soup.

SPEAKER 8: Save the Baby with a dirty sock around your throat.

KATIE HILER: Is Save the Baby like Vicks VapoRub now?

SPEAKER 8: Yes. Yes, it is.

KATIE HILER: OK. Why a dirty sock?

SPEAKER 8: I don’t know.

SPEAKER 9: I generally ignore it and pretend it’s not happening.

KATIE HILER: Does that mean you continue to drink and all that stuff?

SPEAKER 9: Oh, yeah. Yeah, nothing will stop me from drinking, to be quite honest with you.


SPEAKER 11: Lots of water. Zinc lozenges. I know everyone, that’s probably the popular thing, and I– no, you don’t have that in England?

SPEAKER 9: I’ve never even heard of a zinc lozenge. I don’t even know what that is.

SPEAKER 12: I normally take a lot of vitamin C tablets and a lot of juice. And I normally get flu shot.

SPEAKER 13: Actually, I gargle salt water. And I wash hands a lot. And vitamin C, load up on that.

IRA FLATOW: Sounds pretty familiar, right? Especially– I don’t know– that dirty sock and I think I’ve never heard of that one. But is there any hard evidence to back them up, some of these common cold remedies? And how can you tell if it’s the cold you’re at war with, or is it something else that’s infecting you? Well, maybe it’s the flu, or is it allergies? Well, if you want answers, we’ve got some of them. Joining me now to talk about it is Akiko Iwasaki, professor of immunobiology at Yale Medical School. Welcome back to the show.

AKIKO IWASAKI: Thank you, Ira.

IRA FLATOW: Dian Pappas is a professor of pediatrics at the University of Virginia. Welcome.

DIANE PAPPAS: Thank you.

IRA FLATOW: Let’s go right to it, Dr. Iwasaki. When we catch a cold, it always seems to start in your nose. Why is that?

AKIKO IWASAKI: So the common cold virus that causes the cold is actually called the rhinovirus. And the name comes from the fact that the virus replicates in the nose first. So the virus starts to grow inside the lining of the nose, and that is probably why we feel the symptoms first starting in the nose.

IRA FLATOW: And then it spreads to the rest of your body?

AKIKO IWASAKI: So in healthy people, the virus stays in the nose and does not spread to other places. But people with asthma and other respiratory conditions, the virus can spread from the nose to the lung. And that’s where the mucous secretion that is induced by this virus causes the block in the airway. So depending on the host, it can go from the nose, it can stay there, or it can spread.

IRA FLATOW: Mhm. Dr. Pappas, how– and I’ve always wondered about this. You know, you see people who are starting a cold, right? You know they’ve got the first symptoms. How long after you come down with the cold are you infectious to other people?

DIANE PAPPAS: Well, once you get inoculated with the cold virus, it doesn’t take very long before you start to have symptoms. And on days two and three, you’re much more likely– you’re really able to spread that cold very, very easily to other people. So you’re most infectious on the second and the third day of the cold infection.

IRA FLATOW: And how long should the cold last in your body before it turns into something else, like a secondary infection? How do you know it’s just a cold?

DIANE PAPPAS: Well, colds in adults are going to last about five to seven days. And then they’re going to be gone. In children, a normal, uncomplicated cold can go from 10 to 14 days. And so we really don’t start calling it a secondary infection until we’ve passed that 10 to 14 day mark in kids if we’re talking about a sinus infection. There’s some other things kids can get like ear infections, which are extremely common, often during the first week of a cold. So for younger kids under the age of five, probably over half of them will get an ear infection or can get an ear infection with a cold virus. In adults with sinusitis, I would think it would be after the five to seven days that the cold has run its course.

IRA FLATOW: Do kids present themselves differently than adults with symptoms?

DIANE PAPPAS: Kids are different than adults. So younger children tend to have fever at the beginning of their cold, whereas adults tend not to have fever. The symptoms, like we said, in children tend to last longer than it does in adults. Kids are much more likely to be symptomatic. There are adults– and kids can do it too. But in adults, particularly, you can be asymptomatic, although you are infected, and you won’t know that you’re infected. Kids, if they’re infected, they are much more likely to be symptomatic with their colds. They’re much more likely to have complications like ear infections. And then there are certain presentations that are specific to kids because of their airway. Things like croup or things like bronchiolitis that happen in our younger kids.

IRA FLATOW: Dr. Iwasaki, we always have a big debate in our Science Friday office. How do you know if it’s a cold, a sinus infection, or some allergy that’s going around?

AKIKO IWASAKI: Yeah, that’s a good question. Sometimes, the symptoms are difficult to tell apart. Just to clarify, the cold is caused by a virus, and allergy is caused by an allergen, which is not an infectious material. It’s an irritant. And sinus infection is caused most often by bacteria.

So a good sign of bacterial infection is that the mucus turns green or yellow– that’s kind of gross, but– where a cold infection produces mucus that’s clear and watery. And allergy often produces symptoms that are similar to cold. So the mucus is watery and clear.

But the allergy’s dependent on the exposure to the allergens. So if you change the environment– for example, you go from the indoor to the outdoor, or go from one building to another, and you see that your symptoms improve, it is likely a sign of an allergy instead of a cold.

IRA FLATOW: So many questions from listeners. Let’s see if we can get a few of them in. Let’s go to the phones. To Evan in New York. Hi, welcome to Science Friday.

EVAN: Hey, thanks for taking my call.

IRA FLATOW: You’re welcome. Go ahead.

EVAN: As a new public school music teacher, I see about 800 kids a week. I get sick all the time. It’s my first year teaching. What can I do to get over these colds and not take so many days off?

IRA FLATOW: Hm, 800 kids. You’re both blanching at the thought.

DIANE PAPPAS: That’s a lot. The best thing you can do is prevention, right? Once you get the cold, we’re really pretty much stuck. So if you can do your hand washing– soap and water is the best thing you can do. Get your flu vaccine so that you don’t get influenza. And reduce your stress. We know that increased stress– at least, there’s one study that says that’ll increase your rates of infection. Don’t smoke, as smoking increases your susceptibility to colds. But really, it’s soap and water, and keeping your hands out of your eyes and your nose.

IRA FLATOW: Well, let’s talk about how the cold is spread. Is it really spread surface to surface, hand to hand? You touch something, they touch something, you shake hands? Or are you sneezed on or coughed on?

AKIKO IWASAKI: I think the virus can spread in both ways. But a vast majority of the transmission between humans is thought to be by touching the surface, or shaking hands, or touching the door knobs. And sometimes it can be spread by coughing and sneezing as well.

IRA FLATOW: Mhm. So watch those hands. And you say you just need to wash your hands with soap and water. You do not need to use the hand cleaner.

DIANE PAPPAS: Well, the hand cleaner actually may not get everything. So soap and water is your best bet.

IRA FLATOW: And do you have to wash your hands a certain amount of time? Was it sing “Twinkle Twinkle Little Star” or something like that?

DIANE PAPPAS: I don’t know an exact amount of time.

IRA FLATOW: OK, a lot of questions on the phone. Let’s go back to the phones to Adrian in St. Paul. Hi, Adrian.


IRA FLATOW: Hey there. Go ahead.

ADRIAN: So I’ve read articles before that talk about how kids who pick their noses and eat their boogers, it might actually help their immunity. So along that same vein, if a person who has a cold ingests their own mucus, is that potentially helpful, or does it perpetuate a cold more?

AKIKO IWASAKI: I don’t know of any evidence of eating boogers being helpful. In a similar way, when you have a cold, you’re likely swallowing a lot of that virus that is discharged from the nasal cavity anyway. I don’t think there’s any need to actively swallow the cold virus in order to immunize yourself. And again, I don’t know of any evidence that swallowing or eating a cold virus will help.

IRA FLATOW: Are you then reinfecting yourself every time you swallow your own mucus, or is it perpetuating the cold to keep going?

AKIKO IWASAKI: I don’t think so. I mean, once you get the cold, the virus takes its course. And it’s cleared by the immune system. So you know, I’m not sure if there’s anything actively you can do to promote faster clearance, other than to say that getting enough sleep and being stress-free is very important.

IRA FLATOW: Yeah. It’s easy to do these days, right? Let’s go to Sarah in Somerville, Mass. Hi, Sarah.

SARAH: Hi, there. My question is about zinc lozenges. I’ve had terrific luck using zinc lozenges, both to shorten the life of a cold, but especially when I feel one coming on. And I’ve even sometimes taken them just if I’m on an airplane or I feel like I might be getting exposed. So I was wondering about the science behind that, and also any risks associated with consuming zinc.

IRA FLATOW: All right, good question. Let’s get into those home remedies. Does zinc work?

DIANE PAPPAS: So the studies on zinc in adults suggests that they could shorten the duration of cold symptoms. The studies in children are not supportive. And side effects are common. So bad taste and nausea tend to go with zinc. But we really don’t have large, high-quality trials that can let us make clinical recommendations that zinc is the way to go. We just don’t have that information.

IRA FLATOW: We had a man-on-the-street little vox populi before we started here, people telling their home remedies. Let’s go through some of them. What about high doses of vitamin C? Now was it Linus Pauling who used it, championed that years ago?

DIANE PAPPAS: Vitamin C is in the same boat with zinc. There are some studies that suggest it may reduce the duration of the cold. But then some further studies with therapeutic trials did not show the same effect. So we just don’t have the information to say that vitamin C is effective, and can’t really recommend it at this point.

IRA FLATOW: Chicken soup.

DIANE PAPPAS: Chicken soup, there’s a study. So if you sip hot chicken soup, you can increase the flow of nasal mucus. Now whether that’s a benefit or not, that’s probably personal preference. But it does do something.

IRA FLATOW: Mhm. So it at least makes you feel a little better, right?

DIANE PAPPAS: Yeah. Now the effects are gone within 30 minutes, but chicken soup is definitely different than sipping hot water. The chicken soup works better if you want to make your nose run.

IRA FLATOW: Do you know of any connection between the microbiome in our gut and getting a cold? Do we know yet, because it’s a relatively new science?

AKIKO IWASAKI: Yeah, I’m not sure if there’s a study that specifically looks at that. But studies from model of flu infection, for example, indicate that the commensal bacteria are important to maintain the immune status of the host so that the bacterial product actually triggers signals in white blood cells that then promote protection when you’re infected with flu. So there’s probably a beneficial impact of the microbiome.

IRA FLATOW: A tweet from A Life Of Health asking about echinacea.

DIANE PAPPAS: We have no evidence that echinacea is useful.

IRA FLATOW: Hm, where do you think all these things come from, all these home remedy ideas?

DIANE PAPPAS: Because we all get the cold. We’re all looking for something that will work.


IRA FLATOW: I’m Ira Flatow. This is Science Friday from PRI– Public Radio International. Talking with doctors Diane Pappas and Akiko Iwasaki about how to– well, right now, we’ve moved into how to cure the common cold with some of these other home remedies, and do they work or not? Let’s go to the phones again. Let’s go to Tom in Philadelphia. Hi, Tom.

TOM: Hi, Ira. I love your show.

IRA FLATOW: Thank you.

TOM: And thanks for taking my call.

IRA FLATOW: Go ahead.

TOM: I’ve read where it’s possible to block off the flow of air to a nasal passage to try and make the environment more hazardous for a virus. Is there any credence to that?

IRA FLATOW: Blocking off– how do you breathe if you’re blocking off the flow?

TOM: Well, you block off your nose and breathe through your mouth.

IRA FLATOW: Uh-huh. I don’t think these doctors have heard these questions.

DIANE PAPPAS: That’s a new one.

IRA FLATOW: Oh, sorry.

DIANE PAPPAS: Well, it’s an interesting–

IRA FLATOW: Yeah. What about that one that we heard where somebody said, wear an old– what was it, an old dirty sock? –around your neck. Have you heard of that one?

DIANE PAPPAS: Not recently.

IRA FLATOW: Maybe that just keeps people away from you, so–

AKIKO IWASAKI: Yeah, probably. I don’t know about blocking air to the nose, whether that’s effective. But warming the nasal temperature inside is probably beneficial. Studies from our laboratories have shown that higher temperature promotes resistance to cold virus. So if you can keep your nose warm, it’s probably a good thing.

IRA FLATOW: Is it because the virus can’t multiply under that kind of condition?

AKIKO IWASAKI: That’s correct. So even increasing the temperature from a nasal temperature that’s normally there, which is about 33 degrees Celsius, to 37 degrees Celsius, which is what you find in the rest of the body. The virus can’t replicate at that temperature. So it’s probably a good idea to keep your nasal passage warm.

IRA FLATOW: What about keeping your room warm, then? I mean, I’m serious. If you raise the temperature and humidity of the rooms, and even though the virus is there and it’s not going to replicate, especially in a doctor’s office where everybody’s sitting together, touching things, and breathing on each other.

AKIKO IWASAKI: Yeah, that’s probably a good idea. Humidity’s very well-known to block transmission of virus from one person to another. And of course, the higher the temperature, the higher the humidity. So it’s probably a good idea to keep your room warm and humid.

IRA FLATOW: Well, there’s something positive we can do. Let’s go see if we get another phone call or two. This one in Fort Lauderdale. Hi, Ari.

ARI: Hi, Ira. Thank you for taking my call today. I have a question for your panelists. What if you know for sure you already have a sinus infection? Is it possible to catch a cold on top of that days later?

IRA FLATOW: Hm. Complications.

DIANE PAPPAS: I think you can always catch a cold.

IRA FLATOW: Yeah. How hard is it for a doctor to diagnose that you have a cold?

DIANE PAPPAS: It’s not any harder than you diagnosing a cold. I mean, we all know the symptoms. We’ve all lived through many, many colds. I mean, I’m ruling out allergies. And kids, we rule out foreign bodies and those sorts of things. But they’re different.

IRA FLATOW: Hm. Any other hints for the– well, now everybody’s going to get together for the holiday season, what to do when we’re all together?

AKIKO IWASAKI: Keep your hands clean and try not to sneeze on each other. And keep the room warm and eat well. And sleep well.

IRA FLATOW: Easy for you to say. All right. Thank you both. This has been highly educational. I want to thank both of you for taking time to be with us. Akiko Iwasaki is professor of immunology at Yale Medical School. Diane Pappas, professor of pediatrics at the University of Virginia. Thank you both, and happy holidays to you.

AKIKO IWASAKI: Happy holidays, Ira.

IRA FLATOW: You’re welcome.


DIANE PAPPAS: Thank you.

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