LULU GARCIA-NAVARRO, HOST:

On yesterday's program, we asked listeners to send in their questions about COVID-19. Now we'd like Allison Aubrey from NPR's Science Desk to provide some answers. We start with Flo Schumacher (ph) from Chicago.

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FLO SCHUMACHER: So my question about the coronavirus is that I know that colds are also caused by the coronavirus, and I was wondering, are these a related coronavirus? Like, how are they the same? And how are they different?

ALLISON AUBREY, BYLINE: Well, coronaviruses are a large family of viruses. And yes, some coronaviruses lead to what we think of as the common cold. But what is spreading around the globe now is a new coronavirus. It clearly can lead to more serious illness in some people. In others, the symptoms are very similar to what you have with the common colds you get - the dry cough. You can get a bit of fever. Of course, the reason for the concern now is that this new coronavirus is very contagious and has certainly led to lots of serious illness and deaths. So there is concern. And yes, this is more serious than the common cold.

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ROBERT JOHNSON: My name is Robert Johnson (ph). I'm calling from Astoria, Ore. We have heard that older people are at a higher risk of COVID-19. At first, I heard the age 60. And now I'm hearing 70. I would like to understand more of what about age makes one more susceptible. Or is age just a convenient proxy for general health?

AUBREY: Generally speaking, older people do seem to be at higher risk. That is certainly what has been documented in China. The average age of death from the coronavirus in China - at least what's been reported so far - has been in the 70s. And it's important to point out that the virus seems to hit older men and smokers particularly hard, as well as people with underlying health problems - so respiratory disease, cardiovascular disease. Among the experts that I've spoken to, there is a consensus that people with these diseases and habits, such as smoking, are at increased risk of serious illness.

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ROBERTA ARONA: Hi. Roberta Arona (ph) from Fontana, Calif. My biggest coronavirus question is, are kids immune to the virus? Is it only adults that get it?

AUBREY: Well, kids are not immune to this new coronavirus. They do get it. But the studies that have come out of China document that small children who get infected tend to have very, very mild symptoms. It's important to point out that what's come out of China - and now we're not just talking about children - we're talking about all of the cases - about 80% of the cases have been very mild, meaning people get sick with fever, a cough. And in some cases, that has meant pneumonia. That has been categorized as mild disease. So yeah, in some cases, it looks nothing more than a common cold. And other cases - much more serious symptoms.

GARCIA-NAVARRO: And finally we got this question from Elizabeth Bird (ph) of Bozeman, Mont. And I'm going to paraphrase it here - so no answering machine beep this time. Allison, she wants to know how long the virus can live on surfaces like chairs or pieces of mail. That's an important question.

AUBREY: So the way that this virus is thought to spread is via respiratory droplets. And what that means is that when an infected person sneezes or coughs, little droplets containing virus, you know, come out of your mouth or come out of your nose. And then what happens is if a person is walking by and one of these little droplets lands on that person - that person then touches their eyes - nose or mouth, they can be infected. That's how you get this person-to-person transmission. What we know so far is that these viruses can land on surfaces and contaminate them. But the virus is not thought to live very long on these surfaces. Nobody can say precisely. But the estimates I've been given by several infectious disease experts is that they tend to live on surfaces for hours - certainly not for days.

GARCIA-NAVARRO: NPR's Allison Aubrey. Allison, thank you so much.

AUBREY: All right. Thank you very much.

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