By Dennis Thompson
MONDAY, July 27, 2020 (HealthDay News) – Face masks may help prevent the spread of COVID-19 among people trapped in a room with an infected “super spreader”, according to a new Swiss study.
Most people infected with a typical COVID viral load do not flood the air with respiratory droplets infected with coronavirus, and the risk of catching the virus tends to be low, according to estimates.
But a severely infected person who coughs frequently can fill a poorly ventilated room with up to 7.4 million copies of the coronavirus for every cubic meter of air, according to researchers Michael Riediker and Dai-Hua Tsai of the Swiss Center for Occupational. and Environmental Health in Winterthur.
“The implications of these findings for daily life and the workplace are that individuals may be at risk of infection if they spend more than a few minutes in a small room with someone infected with COVID-19 and having high viral load, ”Riediker and Tsai concluded.
The study “also highlights the importance of wearing a mask,” said Dr. Aaron Glatt, president of medicine and chief of infectious diseases at Mount Sinai South Nassau. “Wearing a mask clearly helps, and it will decrease the ability of these super spreaders to spread so much.”
For this study, Swiss researchers gathered data from a handful of previous studies that tracked how much coronavirus the average infected person will emit when breathing normally, as well as the virus released by a very sick person who is coughing. frequently.
The team then used a mathematical model to estimate the amount of virus likely to be released by a patient emitting low or strong in the air of a closed room.
A COVID-19 patient with a high viral load would be expected to release a large amount of the virus into the air, especially when he coughs, the researchers found.
These so-called super spreaders aren’t very common, but if they’re engaged in activities like talking loudly or singing, their viral emissions can increase by 1 to 2 orders of magnitude, the researchers said.
When it comes to the risk to people sharing the room with COVID-19 patients, people at rest tend to breathe about half a cubic meter of air every hour, the researchers say.
“So a person spending time in a room with an individual emitting at a typical rate and breathing normally has the chance to inhale only a few copies of the virus while standing away from that person,” the study said.
However, people who exercise can breathe up to six times more air than a person at rest, swallowing several cubic meters of air per hour, according to the researchers. These people are obviously at a higher risk, especially if they are in a small room with someone who is coughing.
The study was published on July 27 in the journal JAMA network open.
“This mathematical modeling study shows that when individuals are engaged in activities that result in heavy breathing, such as singing or exercising, there is a greater chance of transmission because more particles emanate from their body,” said said Dr Amesh Adalja, a senior researcher at the Johns Hopkins Center for Health Security in Baltimore. “This study is consistent with what has been observed epidemiologically with outbreaks in choir practice, for example.
“The implication is that when engaged in these type of activities, it is really important to ensure that no sick people participate and that social distancing is practiced with a higher degree of rigor,” said Adalja.
There are downsides to the new study. Because it is a mathematical model, its results cannot be directly applied to the real world, Glatt noted.
The study also does not provide all the information needed to prevent the spread of COVID-19 because it cannot estimate the actual risk of infection posed by the amount of virus in the air, noted Dr Michael Klompas, an infectious disease physician and associate hospital epidemiologist at Brigham and Women’s Hospital, Boston.
“We don’t care if this virus is in the air or not. We do care if you will be infected or not,” Klompas said. “It’s a good building block and a useful background study, but it doesn’t give us the answer to what we want to know.”
That said, wearing a mask would prevent super spreaders from filling the air with viruses, Glatt concluded.
“It’s amazing why people are so resistant to wearing a mask,” Glatt said. “They have to understand that they are not wearing the mask for themselves. They are wearing the mask for people who are unfortunately not able to protect themselves. They are wearing the mask for everyone in the world, not for themselves- same. “
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