A team of Indian and U.S. researchers examined data from 575,071 individuals who were tested after coming into contact with 84,965 people with confirmed cases of COVID-19. That’s an average of seven contacts per case, and a cohort more than 10 times larger than in a previous study from South Korea that mapped how the virus was transmitted.
“It’s the largest epidemiological study anywhere on COVID by far,” said the lead author, Ramanan Laxminarayan of the Center for Disease Dynamics, Economics and Policy, in New Delhi.
Laxminarayan and his colleagues found that just 8% of people with COVID-19 accounted for 60% of the new infections observed among the contacts. Meanwhile, 7 out of 10 COVID-19 patients were not linked to any new cases.
The finding underscores the essential role of super-spreaders in the COVID-19 pandemic: One individual or event, such as in a poorly ventilated indoor space, can trigger a high number of new infections, while others might not transmit the virus at all.
Largest study of COVID-19 transmission highlights essential role of super-spreaders https://t.co/oZdDGu6LZ6
— Los Angeles Times (@latimes) September 30, 2020