How Do You Fend Off The Flu?
FLORA LICHTMAN, HOST:
This is SCIENCE FRIDAY, from NPR. I'm Flora Lichtman. The flu came on fast and furious this year. Deaths from flu so far are slightly above epidemic levels, according to the CDC. Besides getting the flu shot, is there anything you can do to avoid the virus? It seems like everybody has their own strategy, right?
Do you hold your breath as you walk past a cougher nearby? An informal poll found that SCIENCE FRIDAY employees are likely to do this. Are you that person that brings a napkin into the train rather than touching the subway pole? Maybe you go the hand sanitizer route. We want to know your rules for flu avoidance and your thoughts on flu etiquette.
What do you think? Do you think it's rude to get up if someone is coughing nearby, or just good judgment? We'll find out if there's a better way than moving your seat to avoid getting the flu, as well. Are new, speedier vaccines in the works? Call and tell us your flu story. Like, did you guilt someone into getting a flu shot this year? Are you secretly wishing your sniffly co-workers would stay home?
Give us a call: 1-800-989-TALK. That's 1-800-989-8255. Or tweet us @scifri. And we'll find out how well these strategies really work, because we have a flu expert in our studio with us to vet your flu avoidance tactics. Dr. Nicole Bouvier is an assistant professor in the Division of Infectious Diseases at Mount Sinai School of Medicine here in New York. She joins us in our New York studios. Welcome to SCIENCE FRIDAY, and thanks for coming in.
DR. NICOLE BOUVIER: Thanks for having me.
LICHTMAN: Now tell us - introduce us to the flu. Let's do some basic flu biology first. What makes this virus different?
BOUVIER: So, influenza - the disease influenza is actually caused by, in humans, mainly three different strains. There's two strains of what we call influenza A. So there's the H1N1, which caused the pandemic a few years ago. You may remember hearing that. And then there's also H3N2, which is what's circulating right now. And then the third one is influenza B. So any of those three viruses can cause what we know as clinical influenza.
Now, right now, what's circulating in most of North American is the H3N2 virus. And the reason this season is a bit unusual is partly because it's hit a little bit early. So we - usually, we don't see this many people getting the flu this early in the season. And it also - historically, the H3N2 strain has been associated with more what we call morbidity and mortality, basically more illness and more death.
And why that is, we actually don't know. But if you look back at seasons' worth of data from the CDC, years in which H3N2 predominates tends to be the years in which more people get into the hospital and more people die.
LICHTMAN: And what about that early onset this year? First of all, where does it go the rest of the year? And what explains an early presence this year?
BOUVIER: So, flu is actually in humans worldwide. There's also flu in animals. So, you know, we can occasionally get a pandemic from an animal source. But, in general, flu that's adapted to humans is circulating around the globe all year around. So when we're in the summer and not seeing a lot of flu, the Southern Hemisphere is actually in their winter, and they're seeing a lot of flu.
So when we're up here, you know, going to the beach, Australians are having the flu. So it continually circles around from hemisphere to hemisphere. And then, of course, in the tropics, it tends to be either a year-round phenomenon or, you know, there's more than one annual epidemic. So places like Hong Kong will see often two epidemics per year that are separated by months.
So it depends on, really, what climate you're in and what time of the year it is.
LICHTMAN: Well, what climate does flu like?
BOUVIER: So, it seems to not mind the tropics, because it's there. But what we've seen in the lab, at least, is that in temperate climates, it seems to like winter conditions - so, basically, cold and dry. And there's been some work done in animal models in - actually at Mount Sinai, showing that flu transmits between guinea pigs, which is a model that we use to study flu transmission, much better in a cold, dry environment than when you turn up the humidity or turn up the heat.
LICHTMAN: And how - what's its favorite way to travel?
BOUVIER: That's a good question, also, and it's something we don't fully have the answer to. Now, you can imagine many different ways for a respiratory virus like flu to transmit. It can transmit through the air, either because somebody coughs or sneezes a bunch of - you know, sprays on you, or because once the droplet dries out, it can hang in the air for hours and hours and hours, and you can maybe breathe it in later.
You could also imagine that if somebody rubs their nose and either shakes your hand, and then you touch your nose, or if they touch a doorknob that you subsequently touch and then touch your nose, that's a contact transmission. And probably, it transmits by all of these routes, but we actually don't know which one is the most important and which one is most common among humans.
LICHTMAN: Did you just say that it hangs in the air for hours and hours and hours?
BOUVIER: So we don't actually know, all right. That is a known method of transmission for something like measles or tuberculosis. So it's theoretically possible for flu. The thing about flu is that it's actually a quite delicate virus. It doesn't live forever. It's got a structure that, if it dries out, it dies. So it either has to be in some sort of, you know, viscous substance that's going to keep it sort of moist and alive, or if it desiccates, it dies.
So how long flu can survive hanging in the air is actually not really known.
LICHTMAN: Does that mean that if the subway pole feels a little moist, I should avoid that part of it?
BOUVIER: Well, that's actually another interesting question, because, you know, there was some scientific study looking at how long flu lasts on different kinds of surfaces. And under lab conditions, if you put a droplet of flu on a stainless steel surface, it could be cultured - live virus could be cultured from swabs of that spot for up to 72 hours.
BOUVIER: Now, that - take that with a grain of salt, because that was probably a whole lot more virus, and in a different consistency of medium than you would get if somebody rubbed their nose and touched the subway pole. What I can say is that studies that have been done in households, where one person has flu and then gives it to other people in the household, researchers have gone into those houses and swabbed various surfaces that you think would be touched frequently: doorknobs, phones, refrigerator handles, things like that.
And really, the results have not been very good. They can't really culture live flu viruses off of those surfaces. The one surface that seems to have a lot of flu virus, as you might imagine, are children's toys. So, you know, I wouldn't go putting your kids' toys near your nose. But, you know, the subway pole, I would say, is probably not the most likely place to get it, but use some hand sanitizer after you're holding onto it, and you can be extra sure.
LICHTMAN: Well, let's go to the phones. Gabe in Hadley, Massachusetts, welcome to SCIENCE FRIDAY.
GABE: Hi. Thank you.
LICHTMAN: Do you have a question?
GABE: My question is: I'm a cashier at a supermarket, and I make contact with lots of people day in and day out. I recall, previously on this program, hearing something about ants and them licking each other if one ant is sick or an ant is dead. And I'd be curious to know, maybe it's surprising that I'm not getting sick more than I am, and if that may be attributed to my exposure to so many people on a daily basis and strengthening of the immune system.
BOUVIER: That could be the case. You know, if you're an otherwise healthy person, you are going to be more resistant to getting the flu than somebody else who has underlying health conditions or is older or, you know, younger, like less than two.
An interesting study that was done a while back was looking at swabbing flu from banknotes in Europe. And actually, you can swab live flu from banknotes. So it's possible you're exposing yourself to a lot of flu viruses by handling money. But because, if you have a healthy immune system, and you're not really inoculating yourself with enough to come down with a, you know, a case of the flu, you may actually be strengthening your immune system without even realizing it.
LICHTMAN: A sort of alter-vaccination. Thanks for calling, Gabe.
GABE: Thank you.
LICHTMAN: Let's go to Gary in Wichita, Kansas.
GARY: Hi. I got the stomach flu on Christmas Day because I was on the naughty list this year. But I'm curious - I've gotten it before where I couldn't even tolerate liquids, even clear liquids. But I'm curious, because I hear so much about this flu, but the symptoms are much different than the stomach flus I've gotten. What are the scientific - what are the differences between the two? And I'll take my answer off the air.
LICHTMAN: Thank you.
BOUVIER: I'm really glad you asked that question, because stomach flu is a bit of a misnomer. Most viruses - well, in fact, all viruses that cause a typical kind of gastroenteritis like you had are not actually influenza viruses. So stomach flu is just a nickname that has nothing to do with influenza viruses.
So influenza viruses specifically are respiratory viruses. They only cause respiratory symptoms, except in children. Sometimes children do have vomiting or diarrhea with a typical respiratory flu. But generally, adults don't have gastrointestinal symptoms. So you had a different virus, not a flu virus.
LICHTMAN: Norovirus is going around this year, right?
BOUVIER: Yeah, that's probably - it sounds like a norovirus, based on what you're describing. It sort of hits hard and fast and doesn't really make you feel bad for a long time. But that's what it sounds like.
LICHTMAN: Is sneezing a symptom of influenza?
BOUVIER: So, not as much as you might think. So, flu tends to be more coughing than sneezing. Common cold viruses, which are different from influenza viruses - they're things like rhinoviruses, coronaviruses, adenoviruses - which are different families and classes of viruses, cause the common cold. And they tend to be associated more with sneezing, which is sort of a nose phenomenon. In fact, rhinovirus comes from the word rhino, which means nose. Flu viruses tend to cause more sort of lower respiratory tract symptoms - things like coughing, sore throat, feeling like you've got, you know, a frog in your throat, that sort of thing. Sneezing - it's not to say it can't happen, but it's not as common with the flu as it would be with the common cold viruses.
LICHTMAN: Let's talk a little bit about the vaccine. It seemed to be a pretty good match this year, I read.
BOUVIER: Yeah. It's a very good match this year. I think of all of the flu isolates from around the country that the CDC has tested, 91 percent of them so far have been a very good match to the current flu vaccine. So it's a well-matched year.
LICHTMAN: How do they decide which viruses or virus fragments to put in a vaccine?
BOUVIER: It is part surveillance and part guessing. So what they tend to do is when they're looking at the Northern Hemisphere formulation, they'll look at what's circulating in the Southern Hemisphere during our summer. So, you know, they will be sampling viruses from Australia, from New Zealand, from South Africa and try to make an educated guess as to which of those strains are most likely to come up here to our hemisphere during the winter. And often, they get it right, like this year, and sometimes, they get it wrong. And that's the kind of season we have when we have a poorly matched vaccine.
LICHTMAN: This year, there was news about a new vaccine that wasn't made with eggs or live virus. It was insect cells. Can you tell us a little bit about it?
BOUVIER: So the traditional flu vaccine is, basically, they take whatever strain they think is the best virus candidate and inoculate it into eggs - which, as you can imagine, you need a lot of hens laying a lot of eggs to make millions of vaccine doses. So this new technology is - relies on an insect virus called a baculovirus. And what you do is you engineer this virus to have the gene for the hemoglutinin protein of flu, and that's the protein that the flu uses to attach to cells that it wants to infect.
And it's the most immunogenic protein of flu, meaning it's the one that provokes the largest immune response. So what they do is they put the gene for the hemoglutinin protein into this insect virus. Then they use the insect virus to infect insect cells. And in the process of making its own proteins, the insect virus will also, as a byproduct, make the flu protein. Then they purify it out, and that becomes your vaccine.
LICHTMAN: Is it easier or faster to produce?
BOUVIER: It is faster because the insect cells, you can keep them in the freezer until you need them. And then you just take them out and you thaw them, and you do what we call expand them. You basically let them grow for a while, until you have a lot of them, then you just put a lot of cells with the insect virus in lots of vats and let - just let it go. So you don't have to worry about having lots of hens hanging around, just waiting to lay your eggs in the case of a pandemic.
LICHTMAN: You're listening to SCIENCE FRIDAY, on NPR. I'm Flora Lichtman talking with Dr. Bouvier about the flu. Let's go back to the phones, because people have some interesting things to say - Amy in Manhattan.
AMY: Well, in addition to all these other things, I try to keep a rule that, you know, my germs on one hand, and my - and other people's germs on the other hand, like the right hand. So I'll shake hands with my right hand, and I try not touch my face with my right hand. But, you know, if I need to scratch my nose or something, I'll use my left. And...
LICHTMAN: What do you think about that strategy?
BOUVIER: It's actually part of what has been studied under the heading of non-pharmaceutical interventions, and that's basically things you can do that are not drugs or vaccines to prevent yourself from getting the flu. And so what they've done is - in studies, you take a group of people who are told to just go about their normal lives and a group of people who are told, you know, wash your hands frequently. Do what we call hand awareness, meaning think about where your hands are and try not to touch your face. Do things like cover your sneezes with your elbow instead of with your hand, and sometimes even wearing facemasks. And of those studies, hand awareness and hand hygiene usually turns out to be one of the most effective ways of not giving yourself the flu. So...
AMY: It seems validated.
BOUVIER: Yes, it has been.
LICHTMAN: Thanks for calling, Amy.
AMY: Thank you.
LICHTMAN: What about the universal flu vaccine, the holy grail of seasonal influenza vaccines? How far are we from that?
BOUVIER: It's a little bit hard to say. I think we're inching closer. So one of the problems with the flu viruses is that, for reasons that are kind of complicated, they're very good at subtly changing themselves year after year so that it doesn't affect how they infect or how they replicate, but it does affect how your immune system recognizes them sort of the second time around. And that's why we need to get annual flu vaccines. So it turns out that there are very few parts of the flu virus - we call them epitopes - which are so crucial, that their function is so important, that they cannot change.
If this part of the protein changes, it's going to result in a dead virus. And, you know, we have identified a couple of those, but it turns out that these epitopes do not stimulate a really good immune response when you get either a regular vaccine or when you get the flu. So what researchers are doing now, including my group at Mount Sinai, are looking at how we can alter these epitopes so we present them to the immune system in a different way, almost forcing the immune system to recognize these constant epitopes, make antibodies against it. And then, if you get infected with the flu, you have the antibodies to this constant region that can't change. So it's hard to say. There's a lot of strategies that are sort of under way, but I think it's possible. It's just we need some more work.
LICHTMAN: In about the minute we have left, do you have other tips for people who want to avoid getting flu? Let's say they've already gotten their flu shot. What should they do?
BOUVIER: OK. I have to say, if you haven't gotten your flu shot, get it, because I'm a doctor and I have to say that.
BOUVIER: But it depends on who you are. If you're someone who has certain comorbidity, certain diseases, if you're pregnant, you must get vaccinated. But other than that, I think the things that have shown to work best are things like hand-washing. And if you don't have access to a sink, you can use an alcohol-based sanitizer. You just have to put enough on so your hands are really wet, and you have to let it dry, and then that'll kill the flu virus on your hands.
You have to be aware of where your hands are. If you sneeze or cough, do it into your - in the crook of your elbow instead of in your hand. Try to avoid sharing utensils with people. If you know someone sick, try not to be in their orbit, because the closer you are to them, the more likely you can get flu from them. And they're mostly just commonsense things. But to various degrees, they have been shown to be effective.
LICHTMAN: Yeah, the hand sanitizer thing is interesting, and we really have like 15 seconds, because a cold, it doesn't work as well on, right?
BOUVIER: It does some of them, but some of them it doesn't. So flu, it does kill.
LICHTMAN: Good to know. Thank you for joining us today.
BOUVIER: Thanks for having me.
LICHTMAN: Dr. Nicole Bouvier is an assistant professor in the Division of Infectious Diseases at Mount Sinai School of Medicine here in New York. And stay with us, because we have some astronomy news coming up.
(SOUNDBITE OF MUSIC)
NPR transcripts are created on a rush deadline by a contractor for NPR, and accuracy and availability may vary. This text may not be in its final form and may be updated or revised in the future. Please be aware that the authoritative record of NPR’s programming is the audio.