Ten scientific reasons in support of airborne transmission of SARS-CoV-2
Tremendous researches have been conducted since the start of the Covid-19 pandemic. Trisha Greenhalgh and colleagues published a paper in the Lancet journal under the title “Ten scientific reasons in support of the airborne transmission of SARS-CoV-2“. The summary of this paper is given below:
Objective:
To provide evidence that SARS-CoV-2 is transmitted primarily by the airborne route.
Method:
The summary has been developed by using currently available evidence and scientific and medical knowledge.
Findings:
- Evidence that supports the hypothesis of SARS-CoV-2 being transmitted primarily by the airborne route are as follow:
• Long-range transmission and overdispersion of the basic reproduction number suggest the dominance of aerosol transmission.
• There has been data mentioning long-range transmission of SARS-CoV-2 between patients in adjacent rooms but never in each other’s presence.
• Asymptomatic or presymptomatic transmission of SARS-CoV-2 is a key way SARS-CoV-2 has spread around the world. This supports the predominant airborne mode of transmission.
• SARS-CoV-2 transmission is higher indoors as compared to outdoors and transmission is substantially reduced by indoor ventilation.
• Despite undertaking strict contact-and-droplet precautions and using personal protective equipment (PPE) designed to protect against droplet but not aerosol exposure, nosocomial infections have been documented.
• Viable SARS-CoV-2 has been detected in the room air.
• In COVID-19 hospitals, SARS-CoV-2 has been found in air filters and building ducts; only aerosols can reach such locations.
• Studies including infected and uninfected animals connected with an air duct have shown transmission of SARS-CoV-2 that can be adequately explained only by aerosols.
• There is no study that provides concrete evidence that disproves the hypothesis of airborne SARS-CoV-2 transmission.
• There are fewer data to support other dominant routes of transmission.
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