Coronavirus can be transmitted via air: CCMB study

Hyderabad: A collaborative study by a group of scientists from CSIR-CCMB, Hyderabad, and CSIR-IMTech, Chandigarh, with hospitals in Hyderabad and Mohali confirms the airborne transmission of SARS-CoV-2. The study is now published in the

Journal of Aerosol Science.

Earlier, the exact mechanism of the spread of coronavirus SARS-CoV-2 has remained elusive. Covid-19 was thought to spread by surfaces, epidemiologists found that countries that wore masks during the pandemic were affected less severely. However, quantitative evidence that shows the infectious coronavirus particles in the air was lacking.

The CCMB scientists analyzed the coronavirus genome content from air samples collected from different areas occupied by COVID-19 patients. This included hospitals, closed rooms in which only COVID-19 patients spent a short period of time, and houses of home-quarantined COVID-19 patients. CCMB found that the virus could be frequently detected in the air around COVID-19 patients; the positivity rate increased with the number of patients present on the premises. They also found the virus in ICU as well as non-ICU sections of hospitals, suggesting that patients shed the virus in the air irrespective of the severity of infection.

The study also found viable coronavirus in the air that could infect living cells, and these viruses could spread over a long range of distances. Scientists still suggest wearing face masks to avoid the spread of coronavirus.

"Our results show that coronavirus can stay in the air for some time in absence of ventilation in closed spaces. We find that the positivity rate of finding the virus in the air was 75% when two or more COVID-19 patients were present in a room, in contrast to 15.8% when one or no COVID-19 patients occupied the room in these studies. Our observations are concurrent with previous studies that suggest that the concentration of SARS-CoV-2 RNA is higher in indoor air as compared to outdoor air; and in indoor, it is higher in hospital and healthcare settings that host a larger number of COVID-19 patients, as compared to that in community indoor settings," said Dr. Shivranjani Moharir, a scientist involved in the study.

"As we are back to conducting in-person activities, air surveillance is a useful means to predict infection potential of spaces like classrooms, meeting halls. This can help refine strategies to control the spread of infections," said Dr. Rakesh Mishra, the lead scientist of the work, AcSIR Distinguished Emeritus Professor at CCMB, and Director, Tata Institute for Genetics and Society. He also added that the air surveillance technique is not just limited to coronavirus but can also be optimized to monitor other air-borne infections.