Scientists have been furiously researching COVID-19 coronavirus since it first showed up in Wuhan, China in late 2019. How it’s transmitted has been a key area of that research. Now, a new study says transmission may be as simple as breathing.
How much do we really know about the COVID-19 coronavirus? Millions of dollars are being spent on research, and we may – or we may not – really know how it’s transmitted. If we figure that out, it will go a long way to slowing or stopping the spread of the virus.
A recent study funded by the National Institutes of Health and published in the New England Journal of Medicine found that SARS-CoV-2 can become aerosolized and remain in the air for up to 3 hours. (1) This is similar to the SARS-CoV virus which struck in 2002-2004.
What’s new about this is that scientists now believe that COVID-19 coronavirus may be aerosolized by normal breathing. What remains uncertain is whether this happens in asymptomatic people or in people who have beaten the virus. (See For Some COVID-19 Coronavirus Patients, The Virus Lingers After Symptoms Disappear for more on post-symptomatic contagiousness.)
This new belief by a number of doctors and researchers has led to a push for new advice: face masks for everyone. The US government now seems to be leaning that way, but not all the way.
Dr. Anthony Fauci, head of infectious diseases at the National Institutes of Health, told Fox News the guidance on masks would be changed “because of some recent information that the virus can actually be spread even when people just speak, as opposed to coughing and sneezing.”
The current official advice is that the masks are really only necessary for sick people and those who care for them in close quarters. Dr. Fauci’s comments, coming on the heels of an April 1 letter to the White House from the National Academy of Sciences (NAS,) may lead to a change in the official recommendations.
The April 1 NAS letter said that, although the research isn’t conclusive, “the results of available studies are consistent with aerosolization of virus from normal breathing.”
Until now, we have believed the transmission of the virus occurred via respiratory droplets. These tiny (+/- 1 millimeter) droplets are expelled inot the air when ill people cough or sneeze. They land on surfaces as well as getting into other people’s mucous membranes directly. Touching a virus-laden surface and then touching your mouth, nose or eyes can lead to introduction of the pathogen into your system.
These droplets are also generally believed to fall quickly to the ground. They can be destroyed by various surface sanitizers, but can hang around for up to 72 hours, depending on the surface.
But if the virus can be suspended in the ultrafine mist we expel when we exhale, in other words an aerosol, it becomes much harder to prevent its spread, which in turn is an argument in favor of everyone covering their faces. That would be an added challenge to the surface-to-tissue transmission problem.
The debate around aerosol
The idea of SARS-CoV-2 virus becoming an aerosol and hanging around in the air for up to 3 hours triggered a debate around science and research methods. It seems the research team used a nebulizer to create the viral mist. The argument from those who think the results were overblown is that this kind of mist would never occur under natural circumstances.
The letter from NAS also referenced University of Nebraska Medical Center research that found RNA, or genetic material, from SARS-CoV-2 in the most remote and hard to reach corners of COVID-19 patients’ isolation rooms. This seems to indicate that the virus was aerosolized and then moved around by swirls of air created when medical personnel moved around the rooms.
In two other studies (neither peer reviewed yet) from Hong Kong and China, the idea of using masks as a general defense against the virus gets mixed reviews.
In the Hong Kong study, researchers took samples of the virus from COVID-19 patients and other viral respiratory illnesses and gave some of them face masks. The masks reduced detection of both aerosol and droplets of the virus.
The study from China indicated that the personal protective gear of health care workers may in itself be a source of airborne virus. The researchers looked at Wuhan hospitals and found two primary areas where the virus was aerosolized. These were the bathrooms of patients and the rooms where medical staff removed their protective gear.
The most likely reason for the problem in medical changing areas is the shedding of virus droplets into the air during gear removal. Some are of breathable size, but even those that aren’t can land on surfaces and settle on people’s hands and bodies, according to the NAS panel.
The World Health Organization (WHO) believes that aerosol transmission only occurs during medical treatments involving assisted breathing.
They also caution that detecting the virus’ genetic code in patient rooms didn’t necessarily prove the virus was present in sufficient amounts for transmission. Of course, WHO is also the group who parroted the Chinese government’s lie that the virus couldn’t be transmitted by humans to other humans. So you’ll have to pardon me if I doubt them.
Be smart, be safe and follow the US government’s general guidelines for avoiding the virus and stopping the spread. And as always…keep the faith and keep after it!