COVID-19 appears to linger in the air in crowded or poorly ventilated spaces, and can be spread through tiny airborne particles known as aerosols, according to a new study. At two hospitals in Wuhan, China, researchers found traces of the virus’s genetic material floating in the air in hospital toilets, in an indoor area housing a large number of people, and in rooms where medical staff leave their protective equipment. The study, published Monday in the journal Nature Research, did not provide information on whether airborne particles could cause infections. The issue of how easily COVID-19 can spread through the air has been a hot topic of discussion in recent years. The World Health Organization (WHO) said the risk of this happening is limited to specific circumstances, noting that in more than 75,000 cases in China, no airborne transmission of the virus was reported.
But as cases near 3 million worldwide, scientists are trying to figure out exactly how the infection. People produce two types of droplets when they breathe, cough or speak: a) Larger droplets, which fall to the ground before evaporating, causing infection, mainly through objects they settle on, and b) smaller droplets, which form aerosols and can remain in the air for hours. The researchers, led by Ke Lan of Wuhan University, set up so-called aerosol traps in and around two hospitals in the city that hosted the first cases of the pandemic. They found few aerosols in patient wards, supermarkets and residential buildings, while many were also detected in toilets and other areas where there are many people, including an indoor space near one of the hospitals. Particularly high concentrations of aerosols were found in rooms where medical staff left their protective equipment, which may indicate that particles that contaminated tools were carried into the air when they removed masks, gloves and gowns. The results of the study highlight the importance of ventilation, limiting crowding and hygiene rules.
