The COVID-19 infection caused by SARS-CoV-2 virus is transmitted through air and is an airborne virus, stated a new Lancet Journal report. According to the report there are strong and concrete evidences that prove that the SARS-CoV-2 is spread through air.
Although other modes of transmission like surface can also attribute to the spread of virus, the airborne route is the most dominant one, stated the Lancet Journal report.
According to the report compiled by six experts from different parts of the worlds, the health communities across the world should change their safety protocols immediately.
"Ten streams of evidence collectively support the hypothesis that #SARS-CoV-2 is transmitted primarily by the airborne route."
— The Lancet (@TheLancet) April 16, 2021
10 primary evidences that proves that SARS-CoV2 is transmitted through air
According to a six-expert team, which was led by Trisha Greenhalgh from Oxford University, there are 10 primary evidences that prove the hypothesis of SARS-CoV-2 being spread through airborne route.
Evidence 1: Super-spreader events gives rise to COVID-19 infections
The first major evidence supporting the hypothesis is super spreader events accounting for COVID-19 transmission. According to the experts “such events may be pandemic’s primary drivers”. The experts in its study analysed human behaviours, interactions, room sizes and ventilation in spaces like concerts, cruise ships, care homes, etc. The analysis showed that close contact or touching surfaces don’t explain an increase in the infection.
“Detailed analyses of human behaviours and interactions, room sizes, ventilation, and other variables in choir concerts, cruise ships, slaughterhouses, care homes, and correctional facilities, among other settings, have shown patterns—e.g., long-range transmission and overdispersion of the basic reproduction number (R0), discussed below—consistent with airborne spread of SARS-CoV-2 that cannot be adequately explained by droplets or fomites,” stated the analysis.
Evidence 2: Long-range transmission between people in adjacent rooms
According to the paper the transmission of the SARS-CoV-2 virus between people in adjacent rooms was documented. However, no such transmission was documented when people were in each other’s presence in quarantine hotels. “Historically, it was possible to prove long-range transmission only in the complete absence of community transmission,” the paper said.
Evidence 3: Asymptomatic transmission from people accounts for 59% of transmission
The third evidence brought forward by the people was the fact that those who are asymptomatic and presymptomatic, but not coughing or sneezing, amount to 1/3 or 59% of all the global transmissions and, “is a key way the virus has spread around the world.”
Evidence 4: Transmission of virus is more indoors than outdoors
According to the research, the transmission of the virus was found to be higher indoors compared to outdoors. Moreover, through indoor ventilation, the chances of transmission reduced significantly. “Both observations support a predominantly airborne route of transmission,” the report added.
Evidence 5: Infections have been documented from hospitals where professionals wear PPE
According to the report, nosocomial transmission (transmission originating in hospitals) have been documented from hospitals where health care workers have been wearing PPE (personal protection equipment) that is designed to protect against surface transmission, but not airborne exposure.
Evidence 6: SARS-CoV-2 virus is detected in air
The sixth and the most important evidence coming from the team of experts is that the SARS-CoV-2 virus was detected in air in lab experiment. According to the study, “In laboratory experiments, SARS-CoV-2 stayed infectious in the air for up to 3 h with a half-life of 1·1 h. Viable SARS-CoV-2 was identified in air samples from rooms occupied by COVID-19 patients in the absence of aerosol-generating health-care procedures13 and in air samples from an infected person’s car.”
Evidence 7: Virus was detected in air-filters of hospitals with COVID patients
While other studies previously had failed to identify the virus in air samples, the researchers said that the virus was identified in building ducts and air-filters of hospitals that had COVID patients. According to the researchers the virus could reach such a place only through the medium of air.
Evidence 8: Caged animals got infected by virus transmission through airduct
In the 8th evidence, the experts gave references to several studies that involved caged animals infected with the SARS-CoV2 virus infecting other caged animals that were caged separately. The virus reached other animals through air duct and suggested that it “can be adequately explained only by aerosols.”
Evidence 9: No study so far has provided consistent evidences to refute the claims that the virus is airborne
According to the Lancet report the experts observed that, “No study to our knowledge has provided strong or consistent evidence to refute the hypothesis of airborne SARS-CoV-2 transmission. Individual and environmental variation means that a minority of primary cases (notably, individuals shedding high levels of virus in indoor, crowded settings with poor ventilation) account for a majority of secondary infections, which is supported by high-quality contact tracing data from several countries.”
Evidence 10: Limited evidence that supports other transmission route
The experts in the Lancet report stated, “Ease of infection between people in close proximity to each other has been cited as proof of respiratory droplet transmission of SARS-CoV-2. However, close-proximity transmission in most cases along with distant infection for a few when sharing air is more likely to be explained by dilution of exhaled aerosols with distance from an infected person.”