Most of Covid virus ‘inactivated’ in minutes, says UK study on aerosol risk at short distance - ThePrint

New Delhi: The majority of the SARS-CoV-2 virus is inactivated within 10 minutes of aerosolisation, with a decrease in infectivity to about 10 per cent of the starting value over 20 minutes — making transmission less likely over long distances — according to a study. .

The team notes that the rapid loss of infectivity makes transmission of the infection decreasingly likely as distance from the particle source is increased — even if the particles that contain the virus are small and able to travel long distances. .

They found that a decrease in infectivity at low humidity occurs almost immediately, falling to an average of 54 per cent within five seconds of generation

However, the virus infectivity then remains more stable, only decreasing by an average of 19 per cent over the next five minutes. 

At high humidity, the reduction in infectivity is more gradual, with a steady loss of 48 per cent within the first five minutes. 

The team said that the infectivity decreases as the aerosols, reacting with CO2 within the droplets, become too acidic for the virus to survive, especially in high-humidity conditions

Further research is also needed to confirm the degree to which acidity is involved in the airborne loss of SARS-CoV-2 infectivity at high humidity, and to determine the exact mechanism by which the pH rise deactivates the virus.