The World Health Organization last month acknowledged it “can’t rule out” the possibility the coronavirus can be transmitted through air particles in closed spaces. Scientists are getting concerned that the transmission of SARS-CoV-2 via aerosols matters much more than has been officially acknowledged to date. Proper ventilation might be the best tool to fight this virus. Closed gyms and restaurants can easily spread COVID-19. Seven months into a pandemic, it is time to address this all-important variable, the very air we breathe.
University of Nebraska Medical Center researchers have found, for what appears to be the first time, intact and potentially infectious coronavirus in some tiny airborne particles collected from the rooms of COVID-19 patients.
- The researchers say their study adds to the evidence indicating that the virus, formally known as SARS-CoV-2, can be transmitted in an airborne fashion. “I hope this says, ‘The concern over airborne transmission is legitimate enough that we need to really start taking it seriously and not just pay lip service to it,’ ” said Joshua Santarpia, an associate professor of pathology and microbiology at UNMC. The next question, he said, is how much of a role the airborne route plays in transmitting the virus, compared to other modes, namely the larger droplets produced when people cough or sneeze.
- The report, published in an online archive before peer review by outside scientists, is one of many that researchers around the world are conducting and publishing as they seek answers to questions about the virus and how it operates. The researchers collected SARS-CoV-2 samples from aerosols in five rooms with COVID-19 patients at a height of about a foot above their beds. The patients were talking, and the researchers used a device that’s about the size of a cell phone to sweep up these tiny particles.
- The microdroplets the team collected were as tiny as one micron in diameter, and they were placed in cultures to make them grow. That’s the only way to prove that the virus in aerosols is still viable and can multiply if it infects cells. Of the 18 samples, three of them were able to replicate, which is proof that the aerosolized virus can be contagious. “It is replicated in cell culture and therefore infectious,” Santarpia said.
- This is the latest evidence that face masks are an absolute necessity when indoors, as they can reduce the spread of droplets of all sizes, including microdroplets that a person might eject while speaking. While it’s unclear what kind of viral load in aerosols is needed for infection, it’s evident that the more time you spend indoors with other people who continue to spread aerosols and regular droplets, the more likely you are to be infected.
Santarpia said of the current debate about airborne transmission that it “has become more political than scientific. I think most scientists that work on infectious diseases agree that there’s likely an airborne component, though we may quibble over how large.”