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According to experts, the scientific evidence of the aerial transmission of the SARS-CoV-2 virus by various researchers all point in the same direction, indicating that infectious aerosols are the primary means of human-to-human transmission. is.
It’s not controversial.
The science behind aerosol propagation is “clear, but unacceptable in many areas,” said Dr. Trisha Greenhal. Medscape Medical News..
“In particular, some evidence-based medical movements and infectious disease clinicians are significantly resistant to evidence,” added Greenhalgh, a professor of primary care health sciences at Oxford University in Oxford, UK. I did.
“It’s very difficult to understand why because all the evidence is piled up,” Greenhalf said.
“Scientific evidence of diffusion from both near-field and far-field aerosols was clear from the early days of the pandemic, but some circles, including medical journals, were reluctant to admit this,” Joseph G. .Allen, DSc, MPH, said Medscape Medical News When asked to comment.
“This is the week the dam broke down. Three new comments came out … in the top medical journals— BMJ, Lancet, JAMA “We all likewise point out that aerosols are the primary transmission route,” added Allen, an associate professor of exposure assessment science at Harvard University of Public Health in Boston, Massachusetts.
Greenhalgh et al. Found that COVID-19 cases increased in the aftermath of so-called “superspreader” events, SARS-CoV-2 spread to people in various rooms of the hotel, and relatively few infections were detected after outdoor events. I’m pointing out.
Top 10 Reasons
They outlined 10 scientific reasons to support aerial propagation. Commentary Published online on April 15th Lancet:
The superiority of airborne transmission is supported by the long-distance transmission observed at the Superspreader event.
Long-distance infections have been reported between rooms in the COVID-19 Quarantine Hotel, and infected individuals did not spend time in the same room.
Asymptomatic individuals account for an estimated 33% to 59% of SARS-CoV-2 infections and may spread the virus by speaking.
Infection in outdoor and well-ventilated indoor spaces is lower than in closed spaces.
Nosocomial infections have been reported in medical settings where protective measures address large droplets but not aerosols.
Viable SARS-CoV-2 was detected in the air in the hospital room and in the infected person’s vehicle.
Investigators found SARS-CoV-2 in hospital air filters and building ducts.
Not just humans. Infected animals can infect animals in other cages that are connected only through air ducts.
There is no strong evidence to refute airborne transmission, and contact tracing supports secondary infections in crowded, poorly ventilated indoor spaces.
Only limited evidence supports other means of SARS-CoV-2 infection, such as via parameters and large droplets.
“I thought I would summarize [the evidence] To clarify the arguments for and against. We searched hard for evidence of the opposite, but found nothing, “said Greenhalgh.
“Although other routes can contribute, we believe that aerial routes are likely to dominate,” the authors say.
Evidence of airborne transmission was very early, but the US Centers for Disease Control and Prevention, the World Health Organization (WHO), and others reiterated the message that droplets and vectors were the main concern.
Answers to reviews
The top 10 list is also some counterarguments Systematic review It provides conclusive evidence of aerial transmission, funded by WHO and released last month. “The lack of recoverable virus culture samples of SARS-CoV-2 makes it impossible to draw firm conclusions about airborne transmission,” said the researchers involved in the review.
However, Greenhalgh et al. State that “this conclusion, and the widespread distribution of review results, are of concern due to public health implications.”
The current authors also claim that there is already sufficient evidence for aerial propagation. “Policy should change. No further research is needed on this topic. Another policy is needed,” Greenhalg said. “We need front and center ventilation, air filtration as needed, and a mask suitable for indoor wear.”
Allen agreed that guidance is not always in step with science. “All of the new evidence accumulated about aerial propagation since last winter still has widespread confusion in the public about modes of transmission,” he said.Allen is also a commissioner Lancet It is the COVID-19 Committee and chairs the Task Force of the Committee on Safe Work, Safe Schools and Safe Travel.
“It was only last week that the CDC withdrew its guidance on’deep cleaning’and instead correctly stated that the risk of touching the surface was low,” he added. “Science has been clarifying this for over a year, but the official guidance has just been updated.”
As a result, many businesses and organizations continue to focus on “sanitary theaters.” “We are wasting resources on over-cleaning the surface. Unbelievably, many schools are closed one day each week for thorough cleaning and library book quarantine. Shared. The message that air is a problem and not a shared surface is a message that still needs to be strengthened. “
The National Institute of Health, Economic and Social Research Council and Welcome support Greenhalf’s research. Greenhalgh and Allen had no relevant financial relationship to disclose.
Damian McNamara It is a staff A journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases, gastroenterology, and critical care. Follow Damian on Twitter: @MedReporter..