• The coronavirus can rapidly travel 6 feet through the air when an infected person coughs or sneezes.
  • The coronavirus can live for about two days on plastic, cardboard and stainless steel but is active for only three hours on copper surfaces.
  • COVID-19 is a serious illness now because the virus is new, but as immunity spreads it will eventually evolve into a typical, seasonal common cold.

Video Transcript


JOHN WHYTE: Hello. I'm Dr. John Whyte, Chief Medical Officer at WebMD. And welcome to Coronavirus in Context.

Today, we're going to talk about the microbiology and immunology of the coronavirus. And I'm delighted to be joined by Dr. Vincent Racaniello. He is a Professor of Microbiology and Immunology at Columbia University. Dr. Racaniello, thanks for joining me.

VINCENT RACANIELLO: My pleasure. Good to be with you.

JOHN WHYTE: Let's get right to it. Everybody wants to know about the virus and surfaces. Can you explain to us how long coronavirus lives on surfaces? And I know it depends, but can you give our listeners a sense of what we need to know.

VINCENT RACANIELLO: So people have actually answered that question experimentally. They have looked at the virus on different kinds of surfaces, cardboard, plastic, stainless steel, copper. Copper is the best surface for inactivating the virus. It goes away in about three hours. Of course, not many people have copper anything, so this is not terribly useful.

JOHN WHYTE: Just our pennies. And they're not even really copper. But go ahead.

VINCENT RACANIELLO: Right. Cardboard, plastic, stainless steel, there, the virus can last longer, but not forever. I would say at most a couple of days, maybe two days or so. And we don't even know if, after two days, it would be enough to actually infect you. You know, the dose you'd need to be infected is important. And these studies just looking at when the virus went away. So I would say, you know --

JOHN WHYTE: That's a good point. It just looked when the virus went away, which could mean it wasn't even infectious, perhaps.

VINCENT RACANIELLO: Yeah, it would not be enough to infect the person.

JOHN WHYTE: Now, you mentioned cardboard. And I wanted to ask you about how long there, because I saw a recent notice that some folks are suggesting that you don't touch packages for 24 hours. Is there any science to that?

VINCENT RACANIELLO: Well, the study that I mentioned was done in part using cardboard, and the virus will last a couple of days on cardboard. We don't know if it's enough to infect you. But I think a better solution might be to just open the package, take whatever out you need, throw it away, and then wash your hands. And I think that'll take care of all the issues.

JOHN WHYTE: What do you do in your home about cleaning and disinfecting surfaces? What guidance can you give to our listeners?

VINCENT RACANIELLO: So whenever we bring something in from outside, I mean, if it's in, let's say, a carton of milk or something we're not going to throw away right away, we wipe the outside with Lysol disinfectant, and then we make sure we wash our hands afterwards.

And anything like a cardboard box, we empty it out and throw it away. Envelopes, same thing. Take off the envelope. If it's a bill, I throw that away. But throw it away outside. And wash your hands. I think washing your hands is really a big solution to contamination issues.

JOHN WHYTE: What about those kitchen tables, doorknobs, things like that? Do we need to do that if we're in the home and no one's coming in and out?

VINCENT RACANIELLO: No. If no one's coming in and out, the doorknobs, you can leave alone. But if I come in -- I go in once a week to my lab for doing some corona research. So when I come home, I leave my shoes outside. I wash our hands immediately. But that's only because I've come in from the outside. If no one's coming in and out, you don't need to do all that. JOHN WHYTE: And we're seeing different estimates now of how far the virus can travel. And you know a lot about viruses. And we kind of have this 2 meter, 6 feet type of approach that, you know, when we cough or sneeze, that's how far it travels. And hence, the social distancing of 6 feet. What would you say about how far it can travel?

VINCENT RACANIELLO: I think a couple of meters, 6 feet is a perfect compromise. We think most of the travel is just short distances, droplets that we produce, they fall to the ground pretty quickly. Probably there are a few droplets that have longer distances, and they may travel farther and have some virus, but there are very few reports of those being able to infect people. So I think keeping our distance really will do it.

JOHN WHYTE: Is it aerosolized? Do we need to be concerned about that?

VINCENT RACANIELLO: So when you say aerosol, of course, you mean the tiny droplets that can go 100 feet or more, which is what we see with the measles virus, and is not the case for this virus on the whole. There may be a few exceptions. There's some what we call "super-spreaders" that make aerosols, but they're very rare. So the majority of people are just making the larger droplets that are flowing to the ground quickly.

JOHN WHYTE: As a microbiologist and an immunologist, you must have some perspective on whether masks and coverings are protecting us. What are your thoughts on that?

VINCENT RACANIELLO: Masks are definitely protective. We have known that for years from China's experience, with the first SARS, the masks, they were helpful. They're certainly going to be helpful. And I'm not sure why the US has been reluctant to promote widespread mask use. But as you know, recently, it's been recommended that we all wear masks. In my state, which is New Jersey, you have to wear one now when you go to a supermarket. They're the most effective.

JOHN WHYTE: You have this facial hair, which as we've been talking about, you know, there's been some talk about we shouldn't have facial hair to prevent the spread. What do you say about that as a virologist, not as someone who has facial hair? That's your recommended change.

VINCENT RACANIELLO: I think that if you wear the mask properly, you can -- well, my beard is rather short. Of course, if it were 3 feet long, that would be an issue, obviously, you wouldn't be able to cover yourself with it. So I think that's why the general recommendation for facial hair, take it off. But if it's short enough, I don't think it's a problem.

JOHN WHYTE: You know, we refer to this as a novel coronavirus, because it's new, but there are other coronaviruses. How do you feel this is behaving, so to speak, as other coronaviruses, as well as influenza? We've been talking about temperature and some other elements. Can you give some of your thoughts on how it's the same as some others and how it might be different?

VINCENT RACANIELLO: So I think this SARS-CoV-2 will eventually become the fifth seasonal common cold coronavirus. It may take a few years, but I think those four viruses that cause common colds every winter. They infect a lot of people. No one notices it. They're mild sore throats, cough, and so forth. They're ubiquitous. And I think those all started out, they came from bats hundreds of years ago, entered humans, probably caused small outbreaks. The population was much smaller then. There was no medicine to record it.

And I think this is going to be the same. As it goes around the world, it infects most people in two years or so, then it will be restricted to infecting new kids who come into the world, just like the common cold coronas, and then it will cause a very mild infection, and then older people will be immune. So I think this virus is probably like those common cold viruses when they originated hundreds of years ago, and it will end up the same.

Now, of course, it's causing much more serious disease, because no one is immune to it at all ages, right? So the other common cold coronas, the older population has immunity, and that's why they don't develop serious disease. Until this one gets through the population, we have to deal with it.

JOHN WHYTE: Do you think we're seeing different strands, something different that's been in Europe versus China and here in the US? We see a little bit of a different patient population here in the United States. Is it all the same coronavirus, or you think it's -- is it mutating? Is there different strands? What would you say?

VINCENT RACANIELLO: Well, every virus is slightly different, because one of their strengths is to mutate continuously. If you had COVID-19, and I isolated virus from your upper tract and your lungs, I could find differences in those viruses. They don't usually mean anything in terms of disease. And so we see slightly different viruses in Europe and the US and so forth. We can use those differences to track where the viruses came from. There's an article yesterday showing that the New York virus actually came from Europe.


VINCENT RACANIELLO: That's right. But these changes are as the person in that article said, they're rather boring, these mutations, they don't mean anything, but we can use them as markers.

JOHN WHYTE: But what's the relevance of that, if we knew it came from Europe as opposed to China? Is that just more a policy issue?

VINCENT RACANIELLO: I think it doesn't really matter in the broad sense of the disease. It's the same disease everywhere. If you are curious about where it came from, I think, and if you're interested in policy, restricting travel, and so forth in future outbreaks, it might be interesting.

But I think I had the same reaction to that article. Doesn't really matter where it came from. We have it now. And we have to deal with it.

JOHN WHYTE: What's the role of antibody testing? We've been talking a lot about that. As an immunologist, you, I'm sure, have some perspective. Is that where the future is?

VINCENT RACANIELLO: Antibody testing is now going to be huge. So we messed up the PCR testing. We started too late in this country.

JOHN WHYTE: For diagnostic purposes, whether or not they have the virus.

VINCENT RACANIELLO: Exactly. And now we have a chance to say how many people have been infected. We have a chance to test every person in the US and decide what percent of the population has been infected and what percent has immunity to reinfection. And that can guide us on to whether we can help schools and so forth. It's going to be huge. And I hope we do this part right.

JOHN WHYTE: Now, without giving an immunology lesson, we know that the current tests are qualitative tests, are they not? They tell us whether or not antibodies are present. But does that really tell you that you have immunity from reinfection?

VINCENT RACANIELLO: That's right. These are rapid tests that don't give you a number. They just say yes or no. We do have the other kinds of tests where we can measure your antibodies and say you're probably protected, but those are not going to be used on a massive level. I think those have to be used --

JOHN WHYTE: Why not? VINCENT RACANIELLO: Because those tests are done in clinical laboratories. They depend on taking a tube of blood from the patient. And the logistics of having every American tested that way are just impossible. So we have to depend on the rapid test for now.

JOHN WHYTE: Well, Dr. Racaniello, I want to thank you for taking the time and really helping us understand this virus.

VINCENT RACANIELLO: My pleasure. Thank you.

JOHN WHYTE: And I want to thank you for watching Coronavirus in Context. I'm Dr. John Whyte.