Is Coronavirus Airborne? Experts Weigh In
New questions have arisen about how likely it is to catch the virus through the air.
Many people are wiping down their counters, door knobs, and phones much more frequently than they used to. After all, viruses—like the coronavirus that causes COVID-19—can live on surfaces anywhere from hours to days. But new questions have arisen about whether disinfecting and keeping the recommended six feet away from other people are sufficient enough for avoiding the virus. New cases have people looking to health experts to confirm whether or not coronavirus is airborne. If it's possible that it lingers in the air, then even a socially distanced walk might not be safe.
According to the Los Angeles Times, 60 people from the Skagit Valley Chorale in Washington state decided to still meet for choir practice in early March, seeing as Skagit County had not yet reported any coronavirus cases. However, just three weeks later, an incredible 45 of the members had been diagnosed with COVID-19 or were sick with related symptoms, three had been hospitalized, and two had died. The members claim that they did everything they thought would keep them safe: hand sanitizer at the door, no hugging, and keeping a certain distance between members. Could an airborne virus be the culprit?
The World Health Organization (WHO) takes the position that catching coronavirus from the air is unlikely, except during certain medical procedures. On Mar. 29, WHO released guidelines that underline the necessity of continued protection from droplet transmission (i.e. what might land on you if you were standing close to an infected person with a cough or what might be on your hand if you touched a table onto which someone sneezed) and downplay the possibility of infection via coronavirus in the air. Some infectious disease experts have criticized WHO, saying that it's far too early to determine that airborne coronavirus is not a worry.
Responding to those criticisms, Hanan Balky, MD, assistant director-general for antimicrobial resistance at WHO, told NPR that the organization has yet to see any strong evidence suggesting that the coronavirus can be transmitted through the air.
"If we were to have airborne transmission, we would see cases with no contact before getting ill with that disease…" Balky said. "And we're not seeing that. I think when you look at the sheer number of positive cases, they're happening with very clear mixing and mingling. They're very close with each other…That does not indicate airborne transmission."
But as scientists all over the world are still racing to understand the coronavirus, there are differing opinions and guidelines may shift. One study published in the New England Journal of Medicine on Mar. 17 found that the virus remains "viable and infectious" for three hours within a laboratory controlled aerosol—indicating that air transmission of the virus is plausible, although real-world conditions will vary the amount of time.
"The short answer is, yes, the coronavirus is airborne," says Dimiar Marinov, MD, an assistant professor at the Department of Hygiene and Epidemiology Medical University in Varna, Bulgaria. "However, this is measured in optimal lab conditions. In reality, the life of the virus will depend on the humidity and airflow, which might shorten it significantly. Still, if someone coughed out viral particles just a few minutes ago, you will likely get infected if you breathe the same air."
Shannon Sovndal, MD, a board-certified doctor in both emergency medicine and emergency medical services, explains that some of the divergence in opinions and recommendations comes from comparing coronavirus to a truly airborne disease, like measles, tuberculosis, or smallpox.
These airborne diseases have pathogens so small that they can remain suspended on "dust, liquid, and even air currents" for a significant amount of time, he says.
The coronavirus, which is currently classified as a droplet disease, only faces certain situations where its droplets can become aerosolized. Most of these conditions are created through medical treatments, but, Sovndal says, "droplets can also be aerosolized through sneezing and coughing."
"The difference here is that [these droplets] are bigger and heavier than truly airborne disease. They will remain aloft for a brief period, but then settle. Airborne diseases can float for extended periods of time," he says.
The bottom line here is that, as of right now, research on whether or not (and how) the coronavirus can be transmitted through the air is still inconclusive. However, that's why every expert recommends social distancing.
"The six-foot rule is important and based on science. When you sneeze or cough, the potential extend of a droplet spread is six feet," Sovndal says.
Marinov explains that the fact of the matter is that the virus spreads very "easily" and in many different ways, which is why hand washing and social distancing are of the "utmost importance."
So without a clear answer on how much you should be worried about catching the virus from breathing in the same air as an infected person, the best advice still remains the same: staying home and away from people you aren't isolating with is the best way to stay healthy and stop the spread.