A retrospective cohort study using contact tracing records from more than 27,000 households in Wuhan, China through April 18 estimated an overall SARS-CoV-2 attack rate among people living in the same household of 16%, assuming a mean incubation period of 5 days and a maximum infectious period of 22 days. Individuals \u226560 years old were more susceptible to infection than all other age groups, but were less infectious than children and adolescents \u226420 years. Asymptomatic cases were 80% less likely to infect others compared to symptomatic cases. Symptomatic cases were 1.4-times as likely to infect others while they were presymptomatic, compared to after symptom onset. Mass isolation of cases and quarantine of household contacts, along with lockdown policies, was judged to have caused a 52% decline in the household reproductive number among primary cases and a 63% decline among secondary cases.<\/p>\n
Li et al. (Jan 18, 2021). Household Transmission of SARS-CoV-2 and Risk Factors for Susceptibility and Infectivity in Wuhan: A Retrospective Observational Study. The Lancet Infectious Diseases. <\/i>https:\/\/doi.org\/10.1016\/S1473-3099(20)30981-6<\/a>\u00a0<\/span><\/i><\/p>\n","protected":false},"excerpt":{"rendered":" A retrospective cohort study using contact tracing records from more than 27,000 households in Wuhan, China through April 18 estimated an overall SARS-CoV-2 attack rate among people living in the same household of 16%, assuming a mean incubation period of 5 days and a maximum infectious period of 22 days. Individuals \u226560 years old were…<\/p>\n