US Centers for Disease Control and Prevention (CDC) has updated its public guidance on the spread of coronavirus and said, people can get infected by inhaling very fine respiratory droplets and aerosolised particles carrying the virus or by direct splashes, sprays or touching contaminated hands to mouth, nose, or eye.
The agency states: “Inhalation of air carrying very small fine droplets and aerosol particles that contain infectious virus. Risk of transmission is greatest within three to six feet of an infectious source where the concentration of these very fine droplets and particles is greatest.”
It however also warned that airborne virus can be transmitted even if the infectious source is farther than six feet in certain conditions, largely indoors.
“These transmission events have involved the presence of an infectious person exhaling virus indoors for an extended time (more than 15 minutes and in some cases hours) leading to virus concentrations in the air space sufficient to transmit infections to people more than 6 feet away, and in some cases to people who have passed through that space soon after the infectious person left,” it reads.
The revision is a change in the US federal agency’s earlier stand on most covid transmission being acquired through "close contact, not airborne transmission."
The revision also came weeks after experts said there is consistent, strong evidence to prove that the SARS-CoV-2 virus, is predominantly transmitted through the air. The assessment published in The Lancet journal states public health measures that don’t acknowledge that the transmission is airborne leave people unprotected and allow the virus to spread.
"The evidence supporting airborne transmission is overwhelming, and evidence supporting large droplet transmission is almost non-existent," said Jose-Luis Jimenez, from the University of Colorado Boulder in the US.
"It is urgent that the World Health Organization and other public health agencies adapt their description of transmission to the scientific evidence so that the focus of mitigation is put on reducing airborne transmission," Jimenez was quoted as saying.
The analysis was conducted by six experts from the UK, the US and Canada.