You can't address the routes of transmission without addressing the inherent bias one finds when searching for scientific studies. It's frustrating reading CDC and WHO "briefs" where airborne transmission is downplayed. There is so much political contamination of these organizations I may never trust them again. My job for the last 30 years has been to protect workers from infectious disease. My POV is based on that side of the equation.
CIDRAP: Yet more data support COVID-19 aerosol transmission
CIDRAP, Center for Infectious Disease Research and Policy, is a respected source and is not under the authority of any political body.
One study:
Study 2:
CIDRAP: Yet more data support COVID-19 aerosol transmission
CIDRAP, Center for Infectious Disease Research and Policy, is a respected source and is not under the authority of any political body.
Two studies published late last week in Clinical Infectious Diseases highlight the role of airborne spread of COVID-19 and the importance of efficient ventilation systems. One study found that patients can exhale millions of viral RNA particles per hour in the early stages of disease, and the second tied an outbreak affecting 81% of residents and 50% of healthcare workers at a Dutch nursing home to inadequate ventilation.
One study:
The findings support previous studies that concluded that COVID-19 is mostly likely spread by aerosols rather than large respiratory droplets or contaminated surfaces, the researchers said. Such studies have documented airborne spread in semi-enclosed environments such as a choir practice in Washington state and a restaurant in Guangzhou, China.
"Though we did not study infectivity or transmission probability and other virus releasing activities such as talking and singing, our study demonstrates that exhaled breath emission plays an important role in SARS-CoV-2 emission into the air, which could have contributed greatly to the observed airborne cluster infections and the ongoing pandemic," the authors wrote.
Study 2:
The issue wasn't spread > 6 feet within a room. Rather the issue was the aerosols being spread through the ventilation system.Suspecting that the ventilation system of the affected ward could have contributed to the outbreak, investigators found that an energy-efficient system had been installed in which indoor air was refreshed only when indoor carbon dioxide (CO2) concentrations detected elevated levels. If CO2 levels didn't exceed a certain threshold, unfiltered indoor air was simply recirculated throughout the ward. In contrast, the six unaffected wards were refreshed regularly with outside air....
"We advise that prevention of COVID-19 transmission should take into account the possibility of aerosol transmission in healthcare facilities and other buildings where ventilation systems recirculate unfiltered inside air," the authors of the Aug 28 study wrote.