Authors of more than 500 documents on the disease, warn about the acceptance of this condition of probable contagion
September 29, 2020 Share on FacebookShare Share on TwitterTweet Share on WhatsAppShare
This problem is especially acute, as indicated, in indoor or closed environments, particularly those that are crowded and have inadequate ventilation in relation to the number of occupants and prolonged periods of exposure (REUTERS)
One of the complex conditions facing the world in the face of the coronavirus pandemic is the lack of knowledge that we still have about the disease. As the pandemic circulates, is controlled and reappears, scholars do not stop opening possible doors to new concepts. This is how some measures that were believed to be valuable began to be modified according to new knowledge.
The airborne broadcast of COVID-19 remains a matter of debate. In a document presented by the International Laboratory for Air Quality and Health of the Queensland University of Technology, Brisbane, Australia, which brings together 239 experts from around the world, a call is made to the medical community and relevant national and international organizations to recognize the potential for airborne spread of coronavirus disease. “There is significant potential for inhalation exposure to viruses in microscopic respiratory droplets (microdroplets) at short to medium distances (up to several meters, or room scale), and we are advocating for the use of preventive measures to mitigate this route of airborne transmission. ”, Sentences the document.
Studies by the undersigned and other scientists have shown beyond reasonable doubt that viruses are released during exhalation, speech, and cough in droplets small enough to remain airborne and pose a risk of exposure at greater distances. 1 or 2 m from an infected person. For example, at typical indoor air speeds, a 5 μm droplet will travel tens of meters, much larger than the scale of a typical room, as it settles from a height of 1.5 m to the ground.
The only one who travels
Current guidance from numerous national and international bodies focuses on hand washing, maintaining social distancing, and droplet precautions. Most public health organizations, including the World Health Organization (WHO), do not recognize airborne transmission (REUTERS)
Several retrospective studies conducted after the severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) epidemic demonstrated that airborne transmission was the most likely mechanism to explain the spatial pattern of infections. Retrospective analysis has shown the same for severe acute respiratory syndrome coronavirus. In particular, a study in its review of the records of a Chinese restaurant found no evidence of direct or indirect contact between the 3 parties. In their review of the restaurant's video records, they saw no evidence of direct or indirect contact between the 3 parties.
Many studies conducted on the spread of other viruses, including respiratory syncytial virus (RSV), Middle East respiratory syndrome coronavirus (MERS-CoV), and influenza, show that viable airborne viruses can be exhaled and / or detected in the indoor environment of infected patients. This poses the risk that people who share such environments could potentially inhale these viruses, causing infections and illness.
There are many reasons to expect that SARS-CoV-2 will behave similarly and that transmission through airborne droplets is an important pathway. Viral RNA associated with droplets has been detected in air, and the virus has been shown to maintain infectivity in droplets of this size. Other viruses have been shown to survive just as well, if not better, in aerosols compared to droplets on a surface.
Current guidance from numerous national and international bodies focuses on hand washing, maintaining social distancing, and droplet precautions. Most public health organizations, including the World Health Organization (WHO), do not recognize airborne transmission, except for aerosol generation procedures performed in healthcare settings.
“Handwashing and social distancing are appropriate but, in our opinion – warn the specialists in their document – insufficient to provide protection against virus-bearing respiratory droplets released into the air by infected people.” This problem is especially acute, they indicate, in indoor or closed environments, particularly those that are crowded and have inadequate ventilation in relation to the number of occupants and prolonged exposure periods. For example, airborne transmission appears to be the only plausible explanation for several investigated superpropagation events that occurred under such conditions, and others in which recommended precautions related to direct droplet transmissions were followed.
Add not to subtract
The airborne transmission of COVID-19 is a real risk and control measures must be added to the other precautions taken, to reduce the severity of the pandemic and save lives (REUTERS)
“The evidence is certainly incomplete for all steps in the transmission of COVID-19 microdroplets,” the experts confirm, but stress that following the precautionary principle, all potentially important avenues to slow the spread of COVID-19 must be addressed. .
Provide sufficient and effective ventilation (supply clean outdoor air, minimize air recirculation), especially in public buildings, work environments, schools, hospitals, and nursing homes. Supplement general ventilation with airborne infection controls, such as local exhaust, high-efficiency air filtration, and germicidal UV lights. Avoid overcrowding, especially in public transport and public buildings.
“These measures are practical and can often be easily implemented ; many are inexpensive,” they say . For example, simple steps like opening doors and windows can dramatically increase airflow rates in many buildings.
“It is understood that there is still no universal acceptance of the airborne transmission of SARS-CoV2,” they point out; But in our collective assessment there is more than enough supporting evidence for the precautionary principle to apply. To control the pandemic, pending the availability of a vaccine, all transmission routes must be interrupted. We are concerned that the lack of recognition of the risk of airborne transmission of COVID-19 and the lack of clear recommendations on control measures against the airborne virus will have significant consequences: people may think they are fully protected by adhering to the current recommendations, but in fact, additional interventions are needed in the air to further reduce the risk of infection ”.
This issue is of greater importance now, when countries are reopening after closed closures: getting people back to workplaces and students to schools, colleges and universities. Airborne transmission of COVID-19 is a real risk and control measures must be added to the other precautions taken to reduce the severity of the pandemic and save lives.
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