Over 200 researchers have published a commentary in the journal Clinical Infectious Diseases supporting the idea of airborne transmission of COVID-19. These researchers include epidemiologists, engineers, aerosol scientists, infectious-disease physicians, and clinicians.

Dr. Lidia Morawska (QUT, Australia) and Dr. Donald Milton (University of Maryland, USA) along with the support of 237 other international researchers and scientists have called for the world to take precautions against airborne transmission of COVID-19 infection. COVID-19 has been known to spread through the air via large droplets, when infected people cough or sneeze, but Dr. Morawska, Dr. Milton and other researchers argue that the virus can also spread by smaller droplets (aerosols) that can linger in the air.

The debate over the spread of COVID-19 by floating in the air for extended periods of time is intensifying. WHO has repeatedly disregarded the importance of such airborne transmission, instead focusing on the risks of infection via close contact. 

The WHO coordinator Benedetta Allegranzi on July 7 said in a news conference “We have taken into account that there is emerging evidence on airborne transmission of COVID-19. We have to be open to this evidence and acknowledge its connection with the mode of COVID-19 transmission, along with the precautions that are necessary to undertake.”

COVID-19 and airborne transmission

Since the coronavirus outbreak, scientists believed that the virus spread largely through bits of spit or mucus (droplets) when infected people sneezed or coughed. WHO has long maintained that COVID-19 spreads primarily via these larger droplets, which don’t easily travel farther than about six feet. But recently public health experts and researchers are starting to postulate on the idea that the virus can stay in the air for long periods of time and travel farther as aerosols (less than 5 microns in diameter), produced by people talking, breathing or sneezing.

Laboratory studies have shown that coronavirus can persist in the air for at least 3 hours when artificially aerosolized. Evidence from “superspreader” events also relate to this kind of transmission, as a single infected person at a choir practice infected 45 other people (in Mount Vernon, Washington) many of the infected people were farther than 6 feet from the infected singer. In another case ( in Guangzhou, China) a single person eating at a restaurant on January 24 caused 9 other people to be infected, the airflow pattern analysis showed that viruses propelled as far as 20 feet by an air conditioning unit.

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WHO has consistenyly focused on the importance of handwashing and social distancing to protect against COVID-19 infections. There protective measures are significant but insufficient in protecting against airborne virus that can travel far in enclosed, poorly ventilated spaces.

The researchers expect WHO to consider updating its recommendations for COVID-19 prevention, including; avoiding overcrowding in indoor spaces like public buildings, properly ventilating indoor places, using germicidal UV light for air filtration systems to help prevent against airborne spread of coronavirus.

Some researchers have stated that it is important to address the airborne transmission of COVID-19 no, as in many countries people have returned to offices, restaurants, tourist spots, and bars, improving ventilation will reduce the transmission of the virus in addition to the use of masks.

Meanwhile airborne transmission of COVID-19 has been challenged by some researchers. “I don’t think the overall conclusions are correct regarding airborne transmission of coronavirus,” says Paul Hunter at the University of East Anglia, UK. “They are potentially damaging.” He further adds that the letter released by more than 200 researchers could cause confusion among the public. As taking actions against aerosol spread could give the public false hope and a false sense of security, making them more vulnerable to infection, as they might take less personal care against coronovirus, such as washing their hands and wearing a mask.


SOURCE

It is Time to Address Airborne Transmission of COVID-19
Clinical Infectious Diseases

CITE THIS ARTICLE: "Researchers concerned about airborne COVID-19 transmission," in Geoscience Daily, July 9, 2020, https://geosciencedaily.com/society/airborne-transmission-of-covid-19/.