Can COVID-19 Spread Through The Air?

10:56 minutes

illustration of three people, the one in the center coughing, expelling virus particles, while the two people on either side wearing masks
Credit: Shutterstock

More than 200 scientists this week wrote a letter to the World Health Organization (WHO), reporting there’s a good chance that COVID-19 can be spread through the air. While the WHO has previously said most transmission happens from direct contact with droplets from an infected person’s cough or sneeze, these experts say the virus can actually stay suspended in the air. If this is true, it’s bad news for people who gather in crowded, poorly ventilated spaces. A lot of questions remain, however, about if this is accurate. 

Joining Ira to talk about this story, and more is Nsikan Akpan, a science editor at National Geographic, based in Washington, D.C.

This story is part of Science Friday’s coverage on the novel coronavirus, the agent of the disease COVID-19. Listen to experts discuss the spread, outbreak response, and treatment.

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Segment Guests

Nsikan Akpan

Nsikan Akpan is Health and Science Editor for WNYC in New York, New York.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later this hour we’ll be talking about moving towards action to deal with the changing climate.

First, a large group of scientists came out this week and said that COVID-19 can be transmitted through the air. So what does this mean for those of us trying to stay safe? Joining us today to talk about the story and other news of this week is Nsikan Akpan, science editor at National Geographic in Washington. Welcome to Science Friday.

NSIKAN AKPAN: Thank you for having me.

IRA FLATOW: Nice to have you. Let’s start with this disturbing and sort of confusing news this week, that COVID-19 might be airborne.

NSIKAN AKPAN: So yeah, it’s amazing what a pandemic and a story in The New York Times can do. On Independence Day, Apoorva Mandavilli broke the news that a letter had been signed by these 239 scientists. And they’re making a compelling argument that airborne transmission for COVID-19 is happening. I mean, I think the thing that is really interesting about this letter is that infectious disease researchers have been arguing about airborne spread for decades.

So when people sneeze or cough, they release a spray of respiratory droplets that come in these different sizes. We have the larger droplets that everyone’s talking about. They fall immediately, sort of like raindrops. And so that’s why experts were always telling us to beware of surfaces whenever somebody sneezes around them.

Airborne transmission refers specifically to smaller droplets, or aerosols. Those are typically under 5 to 10 microns. What we know about aerosols is that they linger for really long periods of time and they can travel long distances.

So the questions have always centered around, how long do infectious aerosols last in the air, and for which diseases? We know for measles that the spread of that disease happens via aerosols, and it can happen over long distances, which is why it’s so contagious. A single measles case can infect 18 other people if they’re unvaccinated.

So why this kind of created shockwaves this week is that we haven’t really thought that infectious diseases, like influenza or like the coronavirus, spread through these aerosols. And if they do, it’s going to have some ramifications for our health guidance.

IRA FLATOW: And so far, we really don’t know the truth, right? I mean, that’s the confusing part is that we don’t have enough science to know about exactly how it spreads.

NSIKAN AKPAN: That’s absolutely right. And I think that’s also why the World Health Organization has been a little hesitant in terms of accepting the idea that COVID-19 is spreading via aerosols. I mean, if it is, that really changes what we say about social distancing. Do we need to distance more than six feet?

We know that measles, which we’re saying spreads via aerosols, can spread outdoors. So does that mean that there is a higher risk for spread of COVID-19 outdoors? It just raises a lot of questions that will need to be addressed by scientists before we can really make huge changes to guidance. Although, the World Health Organization did say this week that it’s taking this letter into consideration, and that it might update its guidance.

IRA FLATOW: We’ll have to keep watching that as the science changes all the time on this. Let’s move on. Your team at National Geographic had a recent story about the new epicenters of COVID infections. We are seeing these hotspots popping up all over the place now.

NSIKAN AKPAN: Right. As many know, and I’m sure you know, New York City was the hardest hit epicenter in the United States. But if you look at the data behind the more recent surges, the Big Apple now has rivals everywhere.

So during New York City’s worst two-week period, about 79,000 New Yorkers were diagnosed with COVID-19, which is about 1 in 107 New Yorkers. What we’re seeing with the recent surges is that many areas are experiencing a greater density of cases than New York City during the city’s worst stretch. So Kennedy Elliott, who is our director of interactive storytelling, came up with a map that can show where those worst of the worst hotspots are right now. So for instance, when we look at total cases since the pandemic start, 519 counties have case densities that are worse than one in 100 people, that are worse than what New York saw during its peak period.

IRA FLATOW: That’s crazy. That’s unbelievable, knowing how badly New York was doing.

NSIKAN AKPAN: Yeah, it’s awful. And it also helps explain why America as a whole just experienced its worst two-week stretch of coronavirus cases. More than 640,000 people were diagnosed in just the last two weeks alone.

And I think that the part that makes me a little sad is that it highlights that we missed an opportunity. Cases were plateauing nationwide from April to May. We had about 20,000 to 30,000 cases every single day during that time period. So there was a window there where we had the outbreak sort of under control and where we could have scaled up testing, where we could have scaled up contact tracing across the nation, before these new surges kicked off. I think we still have time to turn the tide before the worst of the worst happens, but I think a lot more people are going to get sick before we do.

IRA FLATOW: Yeah, unfortunately. Let’s shift gears a bit to another big story this week. And that is, the Dakota Access Pipeline will be shut down. Highly unexpected, was it not?

NSIKAN AKPAN: Yeah I mean, it was a pretty tough week for oil pipelines, not just the Dakota Access Pipeline. So the Dakota Access Pipeline runs from North Dakota to Illinois, and it has been facing headaches for the longest of times. When its construction began in early 2016, it set off these huge protests. I think people remember seeing these protests daily on the news.

And the most notable protest was being led by the Standing Rock Sioux Tribe. They were really concerned that the pipeline, after it was constructed, it might spill chemicals into the Missouri River, which they use every day for water. So those protests led to a lot of lawsuits.

And so by the end of 2016 when President Obama was about to leave the White House, he paused construction on the Dakota Access Pipeline, pending an environmental review. When President Trump was inaugurated, one of his first acts was an executive order that reversed President Obama’s decision. And so the pipeline ended up to continue construction and it was operational by June 2017.

However, that didn’t stop the lawsuits. They just kept coming and coming. And this week, a judge in DC’s district court vacated the federal permit for the pipeline until the Army Corps of Engineers finishes its environmental review, which could take years.

IRA FLATOW: So is that considered a huge win for pipeline protesters?

NSIKAN AKPAN: Yeah, it’s huge. The chairman for the Standing Rock Sioux Tribe described the day as historic. But he also said that the pipeline shouldn’t have been built from the very beginning.

IRA FLATOW: Is it possible that this could be overturned again?

NSIKAN AKPAN: Yeah. The Texas company that owns the pipeline said that they plan to file a motion to stay the judge’s decision. And if that fails, they plan to appeal it to a higher court.

IRA FLATOW: So what about other pipelines? You mentioned this was a bad week for a pipeline business.

NSIKAN AKPAN: Yeah, I was talking about this with our environmental reporter Alejandra Borunda. And she said what’s going on is that environmental groups have become really crafty at filing these lawsuits that then end up blocking pipeline permits. So earlier this week, the developers of the Atlantic Coast Pipeline canceled their plans to build a pipeline across the Appalachian Trail because the costs of these lawsuits just became too high. And then also, the Supreme Court denied an emergency bid by the Trump administration to allow construction of the Keystone XL Pipeline, which has faced a lot of the same controversies.

IRA FLATOW: Interesting. Let’s move on to another climate change-related story. And this one just blows my mind. And that is that Siberia is experiencing a rash of forest fires following the first 100-degree days on record in Siberia. Wow.

NSIKAN AKPAN: Yeah, it’s bananas. The Siberian Arctic is experiencing a rash of fires that are burning farther north than they have in years. Hot summer days aren’t unheard of in the Arctic. Along the coast, temperatures stay pretty cool during the summer. But inland, temperatures sometimes get really, really hot.

I think the thing that stands out here is the consistency of the heat. The heat has just been so hot that it really rivals what happened last year in 2019, when we saw a lot of fires in the Arctic. And those two years far exceed anything else that the Arctic has experienced since 2003. And that was according to Maddie Stone, who covered the story for us this week.

IRA FLATOW: And what are these high temperatures doing to the region? Isn’t that a region full of permafrost?

NSIKAN AKPAN: Yeah, that’s why this is so dangerous. Permafrost is this really thick soil, this layer of Earth that extends down several thousand feet in some places. And the thing about it is that it contains a lot of carbon. There’s a lot of methane in there. And the worry is that these fires, it’s going to burn off this topsoil and you’re going to start to see some of this carbon seeping into the atmosphere, which would probably throw off a lot of our climate projections and could be potentially disastrous for generations to come that are dealing with climate change.

IRA FLATOW: I imagine this would be true of the rest of Siberia and other areas where forest fires or the permafrost is melting.

NSIKAN AKPAN: Exactly. This is just something that we’ve been seeing for the past few years, is that temperatures are getting hotter. We’re seeing more of these fires. And it’s a trend that is predicted by climate change research, that the Arctic is going to get hotter and hotter. I believe the Arctic is warming faster than any other place on the planet right now.

IRA FLATOW: Good place to stop because it’s just going to keep getting worse. So keep in touch, Nsikan. Thank you for taking time to be with us today.

NSIKAN AKPAN: Absolutely. Thanks for having me.

IRA FLATOW: Nsikan Akpan is science editor at National Geographic in Washington, DC.

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