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Airborne Transmission Of Coronavirus Is Just As Concerning As Droplet Transmission, According To New Study

New assessment calls to align public health measures with the airborne spread of the virus

A new assessment report on the transmission of SARS-CoV-2 calls out for redesigning the public health measures that only caters to the large drop transmission and asks for including that the virus could predominantly be airborne.

The study reveals that treating the virus as it could spread through the air would save lives and stated that the world needs to change the approach for preventive measures that are already in use.

“It is quite surprising that anyone is still questioning whether the airborne transmission is the predominant transmission pathway for this virus or not,” said co-author Kimberly Prather, a distinguished professor of atmospheric chemistry at Scripps Institution of Oceanography at UC San Diego. “Only by including inhalation of aerosols at both close and long-range can we explain the many indoor outbreaks that have occurred around the globe. Once we acknowledge this virus is airborne, we know how to fix it. Many examples of places have fared much better by acknowledging this virus is airborne from the start. The world needs to follow their lead as soon as possible.”

The University of Oxford’s Trish Greenhalgh and a team of experts reviewed the research on COVID-19 and its transmission through the air and figured out ten lines of evidence to support the predominance of the airborne route.

One of the key examples in the study was one COVID-19 positive individual who transferred the disease to 53 others in an indoor space. Proving the point that the virus is not only being transmitted through large droplets; instead, it is mainly spreading through the air.

“The evidence supporting airborne transmission is overwhelming, and evidence supporting large droplet transmission is almost non-existent,” said co-author Jose-Luis Jimenez, a chemist at CIRES and CU Boulder. “It is urgent that the World Health Organization and other public health agencies adapt their description of transmission to the scientific evidence so that the focus of mitigation is put on reducing airborne transmission.” 

Supporting the researchers’ narrative is that most transmissions of the virus took place indoors, and the transmission rate was even higher in places with bad ventilation. The new research also estimated that 40 percent of all transmission occurs silently, via asymptomatic individuals that don’t even cough or sneeze.

The assessment concluded that the virus could be transferred through long distances, with positive individuals affecting others even from separate rooms. The current SOPs guide people to maintain a 6 feet distance, which as per the research, is not enough and won’t give out effective results in stopping the spread of the virus.

The approach needs to be changed to where people are instructed to avoid crowded indoor spaces, and more concentrated spaces should have better ventilation for effective results.

“We were able to identify and interpret highly complex and specialist papers on the dynamics of fluid flows and the isolation of the live virus,” said lead author Greenhalgh. “While some individual papers were assessed as weak, overall, the evidence base for airborne transmission is extensive and robust. There should be no further delay in implementing measures around the world to protect against such transmission.”

The new research has proven that the prevalent public health measures are not enough in stopping the spread of the virus. While measures to prevent large droplet transmission are important, they are not enough all in all. The focus should be increased to prevent the spread through the airborne passage, which accounts for the large-scale spread so far.

Some of the suggested airborne control measures include ventilation, air filtration, limiting the crowd in indoor spaces, wearing masks, and focusing more on its quality.

“When one starts with the understanding that the virus replicates in the lungs and is exhaled with each breath in a range of particle sizes, some of which can travel well beyond the magical 6-foot curtain posited as the limit for droplets—and can persist in poorly ventilated locations—it is inevitable to conclude that public health strategies must center on those that reduce the airborne spread of respiratory pathogens,” said co-author Robert Schooley, infectious diseases physician and professor at UC San Diego School of Medicine.