An infected person can spread the Coronavirus disease by merely breathing, and not just via large droplets emitted by air, a report by the United States’ National Academy of Sciences (NAS), has said.
“The National Academy of Sciences (NAS) has given a boost to an unsettling idea: that the novel Coronavirus can spread through the air—not just via the large droplets emitted in a cough or sneeze,” it said.
The report said though current studies are not conclusive, the results of available studies are consistent with “aerosolization” of virus from normal breathing.
According to the report, the U.S. Centers for Disease Control and Prevention and other health agencies had insisted the primary route of transmission for severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) is through the larger respiratory droplets.
“Up to one millimeter across, that people expel when they cough and sneeze,” it said.
“Gravity grounds these droplets within one or two metres, although they deposit the virus on surfaces, from which people can pick it up and infect themselves by touching their mouth, nose, or eyes.”
It said if the Coronavirus can be suspended in the ultrafine mist that people produce when they exhale, protection becomes more difficult.
The above explanation strengthens the argument that all people should wear masks in public to reduce unwitting transmission of the virus from asymptomatic carriers.
Also, NAS panel raised concerns that personal protective equipment (PPE) could itself be a source of airborne contamination.
Researchers at Wuhan University in China led by Yuan Liu found the novel coronavirus can be resuspended in the air when healthcare workers remove their PPE, clean the floors, and move through infected areas.
“The presence of viral RNA in air droplets and aerosols indicates the possibility of viral transmissions via these routes,” the NAS panel concludes,” it said.
However, the World Health Organisation’s experts said an analysis of more than 75,000 Coronavirus cases in China revealed no cases of airborne transmission.
According to multiple news reports, CDC is poised to recommend that all people in the United States wear cloth face masks in public to reduce the spread of the virus.
In another work reported by Nancy Leung of the University of Hong Kong and colleagues, they collected respiratory droplets and aerosols from patients with respiratory illnesses caused by viruses; some of the patients wore surgical face masks.
The masks reduced the detection of Coronavirus RNA in both respiratory droplets and aerosols, but only in respiratory droplets among influenza sufferers.
“Our results provide mechanistic evidence that surgical face masks could prevent transmission of human coronavirus and influenza virus infections if worn by symptomatic individuals,” it concluded.