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World Health Organization Antimicrobial Expert Explains Transmission Of Coronavirus

MARY LOUISE KELLY, HOST:

The World Health Organization says the coronavirus is mainly spread by droplets of mucus or saliva created when we cough or sneeze. These droplets can land on nearby surfaces and then be touched by others, which is why you should wash your hands and try not to touch your face. The WHO says the virus is usually not airborne, meaning it can't be suspended in the air and hover there where it might get breathed in. Some experts on virus transmission dispute this, though, saying it's too soon to know.

Well, joining me from WHO headquarters in Geneva is Dr. Hanan Balkhy. She's assistant director general for antimicrobial resistance.

Dr. Balkhy, welcome to ALL THINGS CONSIDERED.

HANAN BALKHY: Thank you for having me on the program.

KELLY: Knowing how the virus spreads is obviously crucial to trying to figure out how to slow it down. Why does the WHO believe that this coronavirus mainly spreads through big droplets that would only be able to travel a few feet?

BALKHY: So we base these guidelines on our knowledge of the pathogen. So what family does the emerging virus belong to? And this one belongs to the coronavirus. So its siblings would be MERS coronavirus, SARS coronavirus and some other less prominent ones. The two pathogens that we know a little bit more about, which is SARS and MERS, are falling under the droplet transmission criteria.

KELLY: The question of airborne versus droplets - airborne would be - what? - a worst-case scenario, meaning it might be able to linger in the air, and people could - would have a better chance of breathing it in.

BALKHY: Absolutely. Not only will it be able to linger in, but actually, it can be disseminated through air currents way much easier than the pathogens that are primarily transmitted through droplet routes. So...

KELLY: So is this a tiny piece of good news that it appears not to be airborne, that it is spread via droplets?

BALKHY: Definitely. That is definitely good news. However, we have to be very cautious and hear where some of the critics out there might say, why are we not calling it airborne? I think when you look at the sheer number of positive cases, they're happening with very clear mixing and mingling, and they're very close with each other. So that does not indicate airborne transmission.

KELLY: So if I hear you correctly, you're not discounting other studies or other views on this. You're just saying until we have solid evidence otherwise, past similar coronaviruses and what evidence we do have thus far points to it being mostly spread by droplets, not airborne.

BALKHY: Yes, absolutely. And I think - we do believe that the WHO has to give guidance for the globe. And I want to reemphasize the situation of the scenarios where you need to do a risk assessment where you would apply airborne isolation because you have specific high-risk areas in your facility that does not allow for proper cleaning, proper hygiene. I cannot put a patient in a negative-pressure room to do a bronchoscope, for example. So I have to apply certain measures based on the scenario that I have at hand.

KELLY: For those who are not sick, to their knowledge, who are not showing any symptoms, should everyone be wearing masks in public?

BALKHY: The immediate answer is they should not be. If you are asymptomatic, then you should not be wearing a mask or a glove outside in the community because we know that it gives you, first of all, the false sense of security. Number two, I can tell you by walking in the streets and talking to my colleagues out there, most of the people who are wearing masks out there are wearing them incorrectly. They're not putting the metal over their nose. They're not securing the leakage of air.

However, what would be a good time to put on the mask? Let's say in the scenarios where you have a patient who is home-isolated because of mild disease - that person has sputum, has phlegm. The burden of the pathogen in his immediate environment needs to be minimized, and putting a mask on at home might help him.

KELLY: You are a pediatrician, and I wonder what strikes you in terms of coronavirus and young people because the early reporting was that children appeared to be much less vulnerable than their parents...

BALKHY: Absolutely.

KELLY: ...And their grandparents. But now we seem to be seeing more and more children being diagnosed and getting sick. What's happening?

BALKHY: Absolutely. And I think, again, this is how this virus is different than the MERS coronavirus that we've experienced, where that one has really, really not affected or inflicted children at any level close to what we see now already three months only into COVID. What I don't have is the details of the comorbidities of the children.

KELLY: You're saying that children, just like adults, might be more vulnerable if they had some underlying condition.

BALKHY: Yes, exactly, because the cases reported from the MERS corona - they were not normal, healthy children, if you will.

KELLY: That's Dr. Hanan Balkhy. She is assistant director general for antimicrobial resistance for the World Health Organization, speaking with us there from WHO headquarters in Geneva.

Dr. Balkhy, thank you so much for your time.

BALKHY: Thank you. Thank you very much, and have a great day. Transcript provided by NPR, Copyright NPR.