Wearing face masks best way to stop airborne spread of Covid-19, says study
Comparing data from the first pandemic epicentre in Wuhan in central China, Italy and New York city, the researchers argue that non-pharmaceutical interventions (NPIs) like social distancing, quarantine and contact tracing work the best when people wear masks.Updated: Jun 13, 2020, 17:15 IST
Wearing face masks in public is the most effective method to prevent person-to-person spread of the coronavirus, a new study says, adding that it is the only way to prevent airborne transmission of the virus.
Comparing data from the first pandemic epicentre in Wuhan in central China, Italy and New York city, the researchers argue that non-pharmaceutical interventions (NPIs) like social distancing, quarantine and contact tracing work the best when people wear masks.
“This protective measure alone significantly reduced the number of infections, that is, by over 78,000 in Italy from April 6 to May 9 and over 66,000 in New York City from April 17 to May 9,” the researchers from Texas A&M University, the University of Texas, the California Institute of Technology and University of California wrote in the paper.
It said both the WHO and the US Centres for Disease Control “largely ignored the importance of airborne transmission route” of the disease even though both emphasised the prevention of contact transmission.
It was only last week that the WHO changed its advice on face masks, saying they should be worn in public where social distancing is not possible.
It said new information showed masks could provide “a barrier for potentially infectious droplets” -- a validation of this research paper.
The organisation had earlier said there was not enough evidence to say that healthy people should wear masks.
The WHO DG Tedros Adhanom Ghebreyesus said on June 6 that “…in light of evolving evidence, the WHO advises that governments should encourage the general public to wear masks where there is widespread transmission and physical distancing is difficult, such as on public transport, in shops or in other confined or crowded environments”.
The new study therefore is particularly relevant to India because wearing a mask is the most inexpensive yet effective way to prevent human-to-human transmission of the virus, if the findings of the study are to be believed.
The paper says that government-mandated wearing of masks helped China in flattening the pandemic curve even as the numbers rise globally.
“In contrast to China, wearing face masks was not mandated and was unpopular in most of the western world during the early outbreak of the pandemic. Advice on the use of face masks was not issued until April 6 by the WHO,” writes one of the authors Renyi Zhang from the department of atmospheric sciences, Texas A&M University.
The peer-reviewed paper was published on June 11 in the prestigious Proceedings of the National Academy of Sciences (PNAS) USA journal: “…analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the trends of the pandemic. This protective measure significantly reduces the number of infections. Other mitigation measures, such as social distancing implemented in the US, are insufficient by themselves in protecting the public.”
Why is wearing a mask critical to combating the pandemic?
Renyi Zhang explained that face covering prevents both airborne transmission and contact transmission.
“On the other hand, social distancing, quarantine, and isolation, in conjunction with hand sanitising, minimise contact (direct and indirect) transmission but do not protect against airborne transmission. With social distancing, quarantine, and isolation in place worldwide and in the US since the beginning of April, airborne transmission represents the only viable route for spreading the disease, when mandated face covering is not implemented.”
“We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with extensive testing, quarantine, and contact tracking, poses the most probable fighting opportunity to stop the Covid-19 pandemic, prior to the development of a vaccine.”