WHO Reviews Available Evidence on Coronavirus Transmission through Air

"Current evidence shows that the COVID-19 virus is transmitted between people through respiratory droplets and contact routes," says the World Health Organization (WHO).

The above means that the virus is found in the kind of big droplets of mucus or saliva created through coughing and sneezing.

The Agency says the virus that causes COVID-19 doesn't seem to linger in the air or be capable of spreading through the air over distances more than about three feet (around a meter).

"Droplet transmission occurs when a person is in close contact (within 1 m) with someone who has respiratory symptoms (e.g. coughing or sneezing,) and is therefore at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposed to potentially infective respiratory droplets (which are generally considered to be > 5-10 μm in diameter). Droplet transmission may also occur through fomites in the immediate environment around the infected person. Therefore, the transmission of the COVID-19 virus can occur by direct contact with infected people and indirect contact with surfaces in the immediate environment or with objects used on the infected person (e.g. stethoscope or thermometer).

"Airborne transmission is different from droplet transmission as it refers to the presence of microbes within droplet nuclei, which are generally considered to be particles < 5μm in diameter, and which result from the evaporation of larger droplets or exist within dust particles. They may remain in the air for long periods of time and be transmitted to others over distances greater than 1 m.

"In the context of COVID-19, the airborne transmission may be possible in specific circumstances and settings in which procedures that generate aerosols are performed (i.e. endotracheal intubation, bronchoscopy, open suctioning, administration of nebulized treatment, manual ventilation before intubation, turning the patient to the prone position, disconnecting the patient from the ventilator, non-invasive positive-pressure ventilation, tracheostomy, and cardiopulmonary resuscitation). In the analysis of 75,465 COVID-19 cases in China, the airborne transmission was not reported," reads the publication. 

"There is some evidence that COVID-19 infection may lead to intestinal infection and be present in faeces. However, to date, only one study has cultured the COVID-19 virus from a single stool specimen. There have been no reports of faecal−oral transmission of the COVID-19 virus to date," the WHO said. 

Source: who.int