Abstract:Objective To explore the risk factors for coronavirus disease 2019 (COVID-19) infection in close contacts of COVID-19 cases in Baoshan District, Shanghai Municipality so as to provide evidence for follow-up prevention and control. Methods We collected the data regarding the epidemic situation and close contacts obtained from field epidemiological investigation and medical observation conducted by Baoshan District Center for Disease Control and Prevention. Risk factors for COVID-19 infection were identified by single factor analysis and multivariate analysis of binary logistic regression model. Results From January 19 to May 31, 2020, among 885 close contacts of the confirmed cases managed in Baoshan District, 19 cases were diagnosed as COVID-19, with the infection rate of 2.15%. The infection rates of close contacts in different age groups showed statistically significant differences (χ2=22.231, P<0.001). There were statistically significant differences in the infection rates among close contacts having different relationships with the cases (P<0.001), close contacts having different frequencies of contact with the cases (Fisher exact test, P<0.001), close contacts having different contact sites with the cases (Fisher exact test, P<0.001), and close contacts having different contact ways with the cases (χ2=118.825, P<0.001). Multivariate analysis of binary logistic regression model revealed that living together as the contact way between close contacts and the related cases (OR=74.302, 95%CI:16.694-330.697) and increase of age (OR=2.112, 95%CI:1.039-4.294) were risk factors for the infection. Conclusion In the process of management of close contacts of COVID-19 cases, we should pay more attention to prevention and control of high risk population who are close contacts living with COVID-19 cases and aged above 60 years.