Speaking just four words an hour increases the spread of Covid 10 times more than just breathing normally, an alarming new study published by the Proceedings of the National Academy of Science (PNAS) has found.And it suggests this is why most of the super spreader events have been social occasions, including gatherings at conferences, bars and restaurants.Most of the health advice on reducing the spread of the virus stresses covering your mouth and nose while sneezing and coughing, but the new research shows even speaking spreads the virus. Using laser light scattering and an optical particle counter, the researchers found previous studies failed to detect intermediate sized speech generated droplets measuring between 5 and 20 microns.These droplets remain airborne for minutes and, if they are inhaled, can take hold in the nose and throat and go on to cause an infection, the study found.It means people who have the virus but are asymptomatic, and who do not sneeze and cough, can still spread the virus just by talking.“Even in the absence of symptoms such as coughing and sneezing, particles spread through speaking may play a key role in the transmission of diseases such as Covid-19,” according to the authors.Dr Joel Rindelaub, an aerosol chemist with the University of Auckland, told Australian Science Media Centre that larger particle sizes produced during speech wouldn’t be capable of reaching the lungs during inhalation.This backed the theory infections begin in the upper airways and instead settle in the nose and throat, he said.“This study concluded that the amount of aerosols produced from talking has been previously under-reported, meaning that activities that promote conversation should have an increased focus when trying to reduce Covid-19 transmission,” he said.“With the large amount of aerosol particles that can be exhaled during conversations, it should be no surprise that most of the reported super spreader events have occurred at social locations, such as bars, restaurants, conferences, and church gatherings.”The research highlights the importance of mask wearing to cut down the spread of the virus.“When engaging in conversation, you are shooting a stream of dirty particles directly at someone’s face,” Dr Rindelaub said.“Sometimes you’ll see people lower their mask when talking to others but really the opposite should be happening.“Conversations are high risk and a high quality N95 mask can keep you and social acquaintances safe,” he said.Previous research on how speech droplets spread Covid by the US National Institutes of Health, published in the New England Journal of Medicine in 2020, ironically found saying the words “stay healthy” produced a very large number of viral droplets to be released into the surrounding air.The “th” sound in the word “healthy” was the offending part of the word.This study found that speaking loudly was more likely to increase the number of viral droplets that were expelled.Breakthrough Aussie cancer treatment: Who is eligibleRanked: Australia’s best and worst IVF clinics
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