After ‘virus airborne’ scare, call for more precautions

After ‘virus airborne’ scare, call for more precautions

Emerging evidence underlines the need for more stringent measures in closed spaces, Bengaluru health experts say

The WHO accepted last week, after 239 scientists wrote it an open letter, that airborne transmission of the coronavirus could occur in healthcare settings. 

The UN agency added that more research was required to explain the different transmission routes of the virus.

WHO had earlier said the primary mode of transmission of Covid-19 was direct, indirect or close contact with infected people.

Health experts in Bengaluru say the acknowledgement means people should take more intensive precautions.

Dr Swati Rajagopal, consultant - infectious disease and travel medicine, Aster CMI Hospital, accepts the possibility of airborne transmission of Covid-19 in closed, crowded and poorly ventilated settings.  She says more definitive evidence is required, but it is important to address all possible modes of transmission. 

“Adequate and effective ventilation in public buildings, hospitals and avoiding crowding in public transport is important. Infection control strategies like exhaust and better air filtration mechanisms should be implemented at workplaces,” she adds.

Outbreaks have been documented in crowded indoor areas: at choir rehearsals, restaurants and fitness classes, she observes. 

Prof C Durga Rao, virologist and retired professor, department of microbiology and cell biology, Indian Institute of Science, says people have a good chance of getting infected in hospitals unless they wear masks. 

He says misrepresentation is rampant, especially when it comes to asymptomatic cases. “The tremendous increase in numbers could be because the tests are not accurate, and many cases could be false positives,” he says. 

Sceptical take 

Dr Giridhara R Babu, epidemiologist, professor and head, Life Course Epidemiology, Public Health Foundation of India, is not sure Covid-19 if airborne.  If it were, he asks, why hasn’t everyone got it after the lockdown was lifted and crowding was common? “Why do low-income countries like Bangladesh which have high population density not have more cases than developed countries?” he wonders.

Analysis of droplet size and the distance they can travel indoors vs outdoors will help derive a conclusive answer. “This might differ in operation theatres and medical settings,” he says.

Testing and treating won’t change if the virus is airborne, but a stricter enforcement of mask wearing and distancing will become necessary, he adds.  “The three Cs — avoid crowds, close contact and closed spaces — will stay in focus,” he says. 

What happened

Early last week, a group of 239 scientists from 30 countries wrote an open letter to the World Health Organisation, saying Covid-19 could be transmitted through the air, and not just by close contact with infected people.  Epidemiologist Maria Van Kerkove, who works with WHO’s Health Emergencies Program, underlines that many of the signatories are engineers, and their observations add “to growing knowledge about the importance of ventilation.”

What to do

Follow all precautions, say doctors.

Wear a mask at all times when you are in community and public spaces.

Avoid crowded, poorly-ventilated areas. If you can’t, always wear a mask.

Ensure good ventilation by keeping windows open.

Maintain hand hygiene and social distancing.

Enforce regular environmental disinfection and cleaning of surfaces.