Heneghan and colleagues' systematic review, funded by WHO, published in March 2021, as a preprint, states: “The lack of recoverable viral culture samples of SARS-CoV-2 prevents firm conclusions to be drawn about airborne transmission”.
This conclusion, and the wide circulation of the review's findings, is concerning because of the public health implications.
If an infectious virus spreads predominantly through large respiratory droplets that fall quickly, the key control measures are reducing direct contact, cleaning surfaces, physical barriers, physical distancing, use of masks within droplet distance, respiratory hygiene, and wearing high-grade protection only for so-called aerosol-generating health-care procedures. Such policies need not distinguish between indoors and outdoors, since a gravity-driven mechanism for transmission would be similar for both settings. But if an infectious virus is mainly airborne, an individual could potentially be infected when they inhale aerosols produced when an infected person exhales, speaks, shouts, sings, sneezes, or coughs. Reducing the airborne transmission of the virus requires measures to avoid inhalation of infectious aerosols, including ventilation, air filtration, reducing crowding and time spent indoors, use of masks whenever indoors, attention to mask quality and fit, and higher-grade protection for healthcare staff and front-line workers.
Airborne transmission of respiratory viruses is difficult to demonstrate directly.
Mixed findings from studies that seek to detect the viable pathogen in the air are therefore insufficient grounds for concluding that a pathogen is not airborne if the totality of scientific evidence indicates otherwise. Decades of painstaking research, which did not include capturing live pathogens in the air, showed that diseases once considered to be spread by droplets are airborne.
Heneghan and colleagues' systematic review, funded by WHO, published in March 2021, as a preprint, states: “The lack of recoverable viral culture samples of SARS-CoV-2 prevents firm conclusions to be drawn about airborne transmission”.
This conclusion, and the wide circulation of the review's findings, is concerning because of the public health implications.
If an infectious virus spreads predominantly through large respiratory droplets that fall quickly, the key control measures are reducing direct contact, cleaning surfaces, physical barriers, physical distancing, use of masks within droplet distance, respiratory hygiene, and wearing high-grade protection only for so-called aerosol-generating health-care procedures. Such policies need not distinguish between indoors and outdoors, since a gravity-driven mechanism for transmission would be similar for both settings. But if an infectious virus is mainly airborne, an individual could potentially be infected when they inhale aerosols produced when an infected person exhales, speaks, shouts, sings, sneezes, or coughs. Reducing the airborne transmission of the virus requires measures to avoid inhalation of infectious aerosols, including ventilation, air filtration, reducing crowding and time spent indoors, use of masks whenever indoors, attention to mask quality and fit, and higher-grade protection for healthcare staff and front-line workers.
Airborne transmission of respiratory viruses is difficult to demonstrate directly.
Mixed findings from studies that seek to detect the viable pathogen in the air are therefore insufficient grounds for concluding that a pathogen is not airborne if the totality of scientific evidence indicates otherwise. Decades of painstaking research, which did not include capturing live pathogens in the air, showed that diseases once considered to be spread by droplets are airborne.
Ten streams of evidence collectively support the hypothesis that SARS-CoV-2 is transmitted primarily by the airborne route.
A virus infects your body by entering healthy cells. There, the invader makes copies of itself and multiplies throughout your body.
The coronavirus latches its spiky surface proteins to receptors on healthy cells, especially those in your lungs.
Specifically, the viral proteins bust into cells through ACE2 receptors. Once inside, the coronavirus hijacks healthy cells and takes command. Eventually, it kills some of the healthy cells. There is some evidence, though, that the Omicron variant doesn’t attack lung tissue as much as other variants did
A virus infects your body by entering healthy cells. There, the invader makes copies of itself and multiplies throughout your body.The coronavirus latches its spiky surface proteins to receptors on healthy cells, especially those in your lungs.
Specifically, the viral proteins bust into cells through ACE2 receptors. Once inside, the coronavirus hijacks healthy cells and takes command. Eventually, it kills some of the healthy cells. There is some evidence, though, that the Omicron variant doesn’t attack lung tissue as much as other variants did
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