While we all know that different variants of SARS-CoV-2 have different transmissibility and infectivity, the root of these discrepancies still remains a mystery. By utilizing a cone-shaped device called the Gesundheit-II which can collect viral RNA exhaled by people infected with SARS-CoV-2, scientists got some idea of how much virus is exhaled out by an infected person.
Researchers recruited 93 people infected with strains including the Alpha, Delta, and Omicron variants between mid-2020 and early 2022. All participants with the latter two strains (Delta and Omicron) were fully vaccinated before catching the virus. Participants were asked to sing and shout into Gesundheit-II for 30 minutes with inevitable coughs and sneezes in between. They observed that participants infected with the Alpha, Delta, and Omicron variants emitted significantly more viral RNA when exhaling than did people infected with other variants like the one first detected in Wuhan, China, and strains not associated with increased transmissibility like Gamma. They showed that one ‘Super Spreader’ person infected with Omicron shed 1,000 times more viral RNA than those infected with Alpha or Delta. Moreover, individuals who contract COVID-19 after vaccination, and even after a booster dose, still shed the virus into the air.
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