How much virus does a person with COVID exhale ? New research has answers
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Remarque : seules les particules inférieures ou égales à 5 microns ont été considérées comme des #aérosols par les auteurs
The infected people faced into a cone-shaped apparatus and sang and shouted — with inevitable coughs and sneezes in between — for 30 minutes, while an attached machine collected the particles they exhaled. The device, called a Gesundheit-II, separated out the fine ‘aerosol’ droplets measuring 5 micrometres or less in diameter, which can linger in the air and leak through cloth and surgical masks.
“This research showed that all three of those #variants that have won the infection race … come out of the body more efficiently when people talk or shout than the earliest strains of the coronavirus,” says John Volckens, a public-health engineer at Colorado State University in Fort Collins.
Study co-author Kristen Coleman, who researches emerging infectious diseases at the University of Maryland in College Park, says this means that people should be “pushing governments to invest in improving indoor air quality by improving #ventilation and filtration systems”.
The study also highlights variation between individuals in the amounts of exhaled virus, which ranged from non-detectable levels to those associated with ‘superspreaders’. One Omicron-infected participant, for example, shed 1,000 times as much viral RNA through fine aerosol as the maximum level observed in those with Alpha or Delta. The researchers say that the root of these discrepancies remains a mystery but could be related to biological factors such as a person’s age. Behaviour might play a part, too: the study’s superspreader coughed more frequently than others.
If new variants are more prone to superspreading, that might drive them to dominate #COVID-19 cases. The team notes that people infected with SARS-CoV-2 exhale much lower amounts of viral RNA than do people infected with influenza, a comparable airborne disease. This suggests that #SARS-CoV-2 could spin off variants that transmit even more virus.
“That is something to be concerned about,” says Alsved.