Epidemiology and transmission dynamics of COVID-19 in two Indian states (30 September 2020)

Summary

A study of more than a half-million people in India who were exposed to the novel coronavirus SARS-CoV-2 suggests that the virus’ continued spread is driven by only a small percentage of those who become infected.

Furthermore, children and young adults were found to be potentially much more important to transmitting the virus — especially within households — than previous studies have identified, according to a paper by Laxminarayan et al. in the journal Science.

Lead researcher Ramanan Laxminarayan, a senior research scholar in PEI, said that the paper is the first large study to capture the extraordinary extent to which SARS-CoV-2 hinges on “superspreading,” in which a small percentage of the infected population passes the virus on to more people. The researchers found that 71% of infected individuals did not infect any of their contacts, while a mere 8% of infected individuals accounted for 60% of new infections.

“Our study presents the largest empirical demonstration of superspreading that we are aware of in any infectious disease,” Laxminarayan said. “Superspreading events are the rule rather than the exception when one is looking at the spread of COVID-19, both in India and likely in all affected places.”