Household secondary attack rate of COVID-19 and associated determinants in Guangzhou, China: a retrospective cohort study
Qin-Long Jing, PhD †
Ming-Jin Liu, BS †
Zhou-Bin Zhang, MPH †
Li-Qun Fang, PhD †
Jun Yuan, MD †
An-Ran Zhang, BS
et al.
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Published:June 17, 2020DOI:https://doi.org/10.1016/S1473-3099(20)30471-0
Summary
Background
As of June 8, 2020, the global reported number of COVID-19 cases had reached more than 7 million with over 400?000 deaths. The household transmissibility of the causative pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains unclear. We aimed to estimate the secondary attack rate of SARS-CoV-2 among household and non-household close contacts in Guangzhou, China, using a statistical transmission model.
Methods
In this retrospective cohort study, we used a comprehensive contact tracing dataset from the Guangzhou Center for Disease Control and Prevention to estimate the secondary attack rate of COVID-19 (defined as the probability that an infected individual will transmit the disease to a susceptible individual) among household and non-household contacts, using a statistical transmission model. We considered two alternative definitions of household contacts in the analysis: individuals who were either family members or close relatives, such as parents and parents-in-law, regardless of residential address, and individuals living at the same address regardless of relationship. We assessed the demographic determinants of transmissibility and the infectivity of COVID-19 cases during their incubation period.
