Introduction:Previous studies have demonstrated significant changes in social contacts during the firstwave coronavirus disease 2019(COVID-19)in Chinese mainland.The purpose of this study was to quantify the time-vary...Introduction:Previous studies have demonstrated significant changes in social contacts during the firstwave coronavirus disease 2019(COVID-19)in Chinese mainland.The purpose of this study was to quantify the time-varying contact patterns by age in Chinese mainland in 2020 and evaluate their impact on the transmission of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Methods:Diary-based contact surveys were performed for four periods:baseline(prior to 2020),outbreak(February 2020),post-lockdown(March–May 2020),and post-epidemic(September–November 2020).We built a Susceptible-Infected-Recovered(SIR)model to evaluate the effect of reducing contacts on transmission.Results:During the post-epidemic period,daily contacts resumed to 26.7%,14.8%,46.8%,and 44.2%of the pre-COVID levels in Wuhan,Shanghai,Shenzhen,and Changsha,respectively.This suggests a moderate risk of resurgence in Changsha,Shenzhen,and Wuhan,and a low risk in Shanghai.School closure alone was not enough to interrupt transmission of SARS-CoV-2 Omicron BA.5,but with the addition of a 75%reduction of contacts at the workplace,it could lead to a 16.8%reduction of the attack rate.To control an outbreak,concerted strategies that target schools,workplaces,and community contacts are needed.Discussion:Monitoring contact patterns by age is key to quantifying the risk of COVID-19 outbreaks and evaluating the impact of intervention strategies.展开更多
基金This work was supported by the Key Program of the National Natural Science Foundation of China(82130093 to H.Y.)Shanghai Municipal Science and Technology Major Project(ZD2021CY001 to H.Y.)Shanghai Rising-Star Program(22QA1402300 to J.Z.).
文摘Introduction:Previous studies have demonstrated significant changes in social contacts during the firstwave coronavirus disease 2019(COVID-19)in Chinese mainland.The purpose of this study was to quantify the time-varying contact patterns by age in Chinese mainland in 2020 and evaluate their impact on the transmission of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Methods:Diary-based contact surveys were performed for four periods:baseline(prior to 2020),outbreak(February 2020),post-lockdown(March–May 2020),and post-epidemic(September–November 2020).We built a Susceptible-Infected-Recovered(SIR)model to evaluate the effect of reducing contacts on transmission.Results:During the post-epidemic period,daily contacts resumed to 26.7%,14.8%,46.8%,and 44.2%of the pre-COVID levels in Wuhan,Shanghai,Shenzhen,and Changsha,respectively.This suggests a moderate risk of resurgence in Changsha,Shenzhen,and Wuhan,and a low risk in Shanghai.School closure alone was not enough to interrupt transmission of SARS-CoV-2 Omicron BA.5,but with the addition of a 75%reduction of contacts at the workplace,it could lead to a 16.8%reduction of the attack rate.To control an outbreak,concerted strategies that target schools,workplaces,and community contacts are needed.Discussion:Monitoring contact patterns by age is key to quantifying the risk of COVID-19 outbreaks and evaluating the impact of intervention strategies.
