This archive report was first published on 18 June 2020.
As the COVID-19 pandemic continues to spread, a recent study has shed light on the alarming rate at which the virus can infect family members and close contacts within households.
Published in The Lancet on June 18, 2020, the research, conducted by Chinese and US-based researchers, analyzed data from 350 COVID-19 patients and nearly 2,000 of their close contacts in Guangzhou, China.
The study found that the average patient had a 2.4% chance of infecting someone they did not live with, but this figure jumped to 17.1% among cohabitants, with the likelihood of household infection being highest among over-60s and lowest among under-20s.
Notably, the researchers discovered that the probability of a COVID-19 carrier infecting a family member or flatmate was significantly higher - 39% - before they started showing symptoms than afterwards.
This suggests that the virus is easily transmissible within its incubation period and may be passed on by individuals who don't know they are infected.
According to the study, isolation within households cut the total number of COVID-19 cases among the study cohort by 20-50% compared with no quarantine.
"Although the effect of case isolation seems moderate, the high infectivity of the virus during the incubation period suggests quarantine of asymptomatic contacts could have prevented more onward transmissions," said Qin-Long Jing from the Guangzhou Center for Disease Control and Prevention.
