Although our understanding of COVID and how it is transmitted has evolved over the past year, a solid consensus emerged at the beginning that aerosols, that is, contaminated droplets, are the most common form of transmission of the virus from person to person. So if you’ve been around someone who has coughed in the past 10 months, you’ve probably found yourself backing away quickly for fear of being infected with COVID-19. But now, a new study published in the journal Proceedings of the Royal Society A on January 20, he discovered that a behavior that we all practice on a daily basis is actually just as likely to spread COVID as to cough, if not more – and that is the simple act of speaking.
Read on to find out what this new research has discovered and to learn more about what you can do to prevent the virus, stop doing it immediately to avoid the new COVID strain, doctors warn.
The research team behind the new study – led by the lead author, Prof. Pedro Magalhães de Oliveira, a fluid mechanics specialist at the University of Cambridge Engineering Department – created a mathematical model to predict how COVID spreads from an infected person in a room, taking into account the size of the space, the number of people present , ventilation and whether people wore masks or not.
The assumption may be that actions that spread many drops – such as sneezing, coughing or screaming – are the most risky in terms of COVID transmission, but this new research from Cambridge University and Imperial College London suggests otherwise. The larger drops associated with the cough fell to the ground at a shorter distance and at a faster rate, while the smaller drops produced by speech carried the virus for more than 2 meters and remained in a room for a long period of time.
“Speaking is a very important issue that must be considered because it produces much finer particles [than coughing] and these particles, or aerosols, can be suspended for more than an hour in sufficient quantities to cause the disease, ”said Oliveira. The Guardian. And to learn more about transmitting COVID, see The strange new way to get COVID, says Study.
The study found that when you’re in a poorly ventilated space and don’t wear masks, talking is much more likely to spread the virus than a short cough. In a modeled scenario, the researchers found that after a short cough, the number of infectious particles in the air decreased after 1 to 7 minutes, notes Live Science. But after speaking for 30 seconds, it took 30 minutes for the number of infectious particles to drop to similar levels. After an hour, a large number of particles were still suspended in the air, enough to make someone else sick. And for more tips on how to stay protected from the virus, check out how this single hygiene habit can protect you from COVID, study says.
If you are in a poorly ventilated room with an infected individual who is speaking, you have a risk of infection of up to 20%, the researchers found. “This analysis illustrates the risk associated with constant speech in closed environments (such as in a classroom) due to a larger mass fraction of liquid resulting in small drops during speech,” concluded the scientists. And for more regular news from COVID, subscribe to our daily newsletter.
The Cambridge team says that “ventilation … is of utmost importance to minimize the risk of infection indoors.” In a note, Oliveira said that the study shows “how these small droplets can accumulate in indoor spaces in the long run and how this can be mitigated with adequate ventilation”.
The team also used their findings to build an online calculator that can help users assess the risk of different indoor situations, given the size of a room and the number of people in it. If you are spending an hour in a medium-sized store with a capacity of 50 people, for example, improving ventilation or wearing three-layer face masks can reduce the risk of infection from 8% to 2%.
“The idea is not to obtain absolute risk figures for the tool, but to use it to see how mitigation strategies impact the risk of infection,” said Oliveira. The Guardian. And to find out more about where the COVID outbreak is the worst at the moment, check out how bad the COVID outbreak is in your state.