For the past several months, controversy has been raging over how SARS-Co-2 causes the virus COVID-19, Travels from one infected person to another. While official guidance has always been vague, some aerosol scientists and public health experts have maintained that the spread of the virus in aerosols passing through the air at distances less than feet and distances is playing a more important role than appreciation.
In July, 239 scientists from 32 countries urged the World Health Organization (WHO) to recognize the possible role of aerobic transmission in the spread of SARS-CoV-2.
Three days later, the WHO said that, under certain conditions, “short-distance aerosol transmissions, especially in indoor locations, such as dense and inadequate air circulation spaces with prolonged infected individuals, could not be ruled out.”
Many scientists expressed joy on social media when the CDC agreed, acknowledging in a September 18 website update that aerosols play a significant role in the spread of the virus. The update states that COVID-19 “can be spread by respiratory droplets or small particles, such as The infected person coughs, sneezes, sings, Talking or breathing. These particles are inhaled into the nose, mouth, airways and lungs and cause infections. This is thought to be the main way the virus is spread. ”
However, three days later, when the CDC mistakenly posted without proper guidance, the controversy arose again due to the guidance.
Currently, the CDC website does not acknowledge that aerosols typically spread beyond SARS-COVI-26 by 6 feet, instead stating: When an infected person coughs, sneezes or talks and drops from his mouth or nose into the air and into the mouths or noses of nearby people. The drops also breathe into the lungs. “
The site says respiratory drops can land on various surfaces, and people can become infected by touching those surfaces and then touching their eyes, nose or mouth. “Current data do not support long-distance aerosol transmission of SARS-CoV-2 in patients with measles or tuberculosis. Short-distance inhalation of aerosols is likely for COVID-19, as are many respiratory pathogens,” he says. Based on this it is not easily recognizable by ‘dot’ transmission, the possibility of short-term transmission is particularly in dense medical wards and inadequate. Ventilated spaces“
Confusion surrounds the use of words like “aerosols” and “drops” because they are not consistently defined. And the word “airborne” has special meaning for infectious disease specialists and public health officials, as the question arises as to whether the infection is easily transmitted by “airborne infections.” If SARS-CoV-2 is easily transmitted by airborne transmission, more stringent measures for infection control will need to be adopted, as is done with airborne diseases such as measles and tuberculosis. But the CDC told CBS News’ chief medical correspondent, Dr. Jonathan Lapuk said that even if airborne spread is playing a role with SARS-CV-2, that role does not seem as important as atmospheric infections such as measles and tuberculosis.
All of this sounds like a scientific discussion of the grass that is deep in the weeds – and it is – but it has a big impact on people trying to figure out how to stay safe during an epidemic. Some pieces of advice are intuitively clear: wear a mask, wash your hands, avoid crowds, stay away from others, be safe outside the house. But what of that “6 feet” rule for maintaining social distance? If the virus can travel indoors for more than 6 feet, isn’t it logical to wear a mask indoors whenever you’re with people who aren’t part of your “pod” or “bubble”?
Understanding the basic science behind how SARS-CoV-2 travels through the air can help us strategize for safety. Unfortunately, there are still many open questions. For example, even if aerosols produced by an infected person can float in a room, and even if the aerosols contain some viable virus, how can we know how important the potential condition is playing in the epidemic?
As we await the answers to the ongoing research, Dr. La. Lapuk turned to three leading scientists to try to clear the air. Acknowledging that science is still not set in stone, based on their current understanding of the spread of SARS-Cavi-2, we have agreed to give them their best advice on how to think about saving themselves. Below, atmospheric chemist Kimberly Stone, airborne virus expert Lance Marr and environmental health professor Donald Milton discuss the best precautions you can take to reduce the risk of infection.
Cleaning the air
Contrary to initial thinking about the importance of transmission through exposure to large respiratory droplets, it turns out that the main way people become infected is by inhaling the virus. This is most common when a person stands within 6 feet of a Covid-19 (with or without symptoms), but it can also occur from a distance of 6 feet.
Viruses in small, gaseous particles, known as aerosols, infect nearby and long-range people. Aerosols can be thought of as cigarette smoke. When they are close to an infected person, they can travel more than 6 feet, delay, bounce in the air, and stay infected for hours. Consequently, to reduce the chances of this virus being inhaled, it is important to take all of the following steps:
Indoors:
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Practice physical distance – the better.
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Wear a face mask when you are with others even when you can maintain physical distance. Infections masks from infected people not only reduce the amount of virus, but also reduce the chances of inhaling the virus.
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Improve ventilation by opening windows. Learn how to clean the air effectively with methods like purification.
Outside:
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Wear a face mask if you can’t take at least 6 feet or, ideally, more physical distance.
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Whenever possible, move out of group activities.
Whether you are indoors or outdoors, remember that your risk increases with the duration of your contact with others.
With the question of transmission, it is not only the public that is confused. Scientists, medical professionals and public health officials are also confused, as they always use the terms “drops” and “aerosols” differently. To clear up this confusion, participants in the August workshop on airborne transmission of CARS-CV-2 at the National Academy of Sciences, Engineering and Medicine unanimously agreed on these definitions for respiratory drops and aerosols:
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Drops Is more than 100 microns and travels like a small cannon and falls to the ground within 6 feet.
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Aerosols Smaller than 100 microns, very concentrated near a person, can travel more than 6 feet and can lengthen and erect in the air, especially in rooms with poor ventilation.
All respiratory activities, including breathing, talking, and singing, produce many more aerosols than droplets. Even at short distances, a person is more likely to breathe aerosols than to be sprayed by a droplet. The exact percentage of transmission by droplets versus aerosols is yet to be determined. But we know from epidemiology and other data, especially hyperventilation events, infection is caused by inhalation of aerosols.
In short, how do we get infected by SARS-Cavi-2? The answer is: in the air. Once we accept this, we can already use the tools to help end this epidemic.
Kimberly a. Prathar, PhD, Special Chair in Atmospheric Chemistry, Scripps Institution of Oceanography, UC San Diego.
Linz C. C, PhD, Lunsford Professor of Civil and Environmental Engineering at Virginia Tech.
Donald K. Milton, MD, Ph.D., Professor of Environmental Health at the University of Maryland School of Public Health.
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