Chinese scientists reveal a high risk of COVID-19 infection in family

A far-reaching study of SARS-CoV-2 transmission in China’s Hunan Province found that the encounters most likely to spread the coronavirus were those between members of the same household.

Kaiyuan Sun at the National Institutes of Health in Bethesda, Maryland, Hongjie Yu at Fudan University in Shanghai, China, and their colleagues analyzed data from 1,178 people in Hunan who were infected with SARS-CoV-2 and more than 15,000 close contacts of the infected people. The team found that communications between people who live together posed the most significant risk of transmission, followed by contacts between extended family members. The transmission risk was lower for social connections and community encounters, such as those on public transport. Every extra day of contact raised transmission risk by 10%, the team found.

The analysis suggests that Hunan’s lockdown increased the risk of viral spread within households, whose members spent more time than usual at home together during a lockdown. But social and community transmission fell during the same period.