The World Health Organization (WHO) has acknowledged the reports of the airborne spread of the novel coronavirus and issued new guidelines on the transmission of COVID-19.
In an updated scientific brief on Thursday, the WHO said that airborne transmission of SARS-CoV-2, the virus that causes COVID-19, could occur during medical procedures that generate aerosols. It stated that the WHO, together with the scientific community, has been actively discussing and evaluating whether SARS-CoV-2 may also spread through aerosols in the absence of aerosol generating procedures, particularly in indoor settings with poor ventilation.
The UN health agency said that more research is needed to elucidate the transmission of SARS-CoV-2 through air. "The virus that causes COVID-19 is predominantly spread from person-to-person. Understanding how, when and in what types of settings SARS-CoV-2 spreads is critical to develop effective public health and infection prevention and control measures to break chains of transmission," the brief maintained.
The WHO said that current evidence suggest that SARS-CoV-2 spreads through direct, indirect, or close contact with infected people who spread the virus through infected secretions such as saliva and respiratory secretions or their respiratory droplets, released when an infected person coughs, sneezes, talks or sings.
The health agency also asserted that asymptomatic people can also spread the virus although the extent of truly asymptomatic infection in the community remains unknown.
"Transmission from infected people without symptoms is difficult to study...Information from contact tracing efforts reported to WHO by Member States, available transmission studies and a recent preprint systematic reviews suggests that individuals without symptoms are less likely to transmit the virus than those who develop symptoms," the WHO said.
The UN health agency also said current evidence suggests that SARS-CoV-2 is primarily transmitted between people via respiratory droplets and contact routes – although aerosolization in medical settings where aerosol generating procedures are used is also another possible mode of transmission - and that transmission of COVID-19 is occurring from people who are pre-symptomatic or symptomatic to others in close contact.
“Transmission can also occur from people who are infected and remain asymptomatic, but the extent to which this occurs is not fully understood and requires further research as an urgent priority. The role and extent of airborne transmission outside of health care facilities, and in particular in close settings with poor ventilation, also requires further study,” the WHO added.
The WHO maintained that limiting close contact between infected people and others is central to breaking chains of transmission of the virus causing COVID-19.
“Quarantine should be in place for 14 days from the last exposure to a confirmed case. If it is not possible for a contact to quarantine in a separate living space, self-quarantine for 14 days at home is required; those in self-quarantine may require support during the use of physical distancing measures to prevent the spread of the virus,” it added.
