The scientific debate over evidence that the coronavirus can float in the air for extended periods of time is intensifying. It was universally believed, since the beginning of the outbreak that the virus was not airborne, but spreads from close contact with infected sources. This evidence evolved over time.
Researchers increasingly think that the coronavirus can stay in the air longer and travel farther in tinier bits, called aerosols, that can be generated by people talking, breathing or singing. These aerosols, which are less than 5 microns in diameter, can linger in the air for extended periods in places without ventilation, possibly infecting people long after the infected person has left.
Scientists are still working out whether an airborne transmission is a common feature of COVID-19’s spread, but evidence suggests it does happen. Laboratory studies have found that infectious coronavirus can persist in the air for at least three hours when artificially aerosolized. One of the first outbreaks in Guangzhou, China was linked to a single positive case eating at a restaurant on January 24. That person infected nine others that night, and an analysis of airflow patterns suggests that viruses were propelled as far as 20 feet by an air conditioning unit.
The mode of transmission informs prevention strategies. The WHO has continually emphasized the importance of social distancing and handwashing to fight the spread of COVID-19. While still important, these measures are insufficient against an airborne virus, which can travel far in enclosed, poorly ventilated spaces. Masks may be necessary for such situations, even with proper social distancing.
Writer: Tiana Bijlani
13/07/2020
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