Risk factors associated with occurrence of COVID‐19 among household persons exposed to patients with confirmed COVID‐19 in Qingdao Municipal, China

Xin, Hualei; Jiang, Fachun; Xue, Aili; Liang, Jiwei; Zhang, Jingfei; Yang, Feng; Han, Yalin

Tracing and isolation of close contacts is used to control outbreaks of coronavirus disease 2019 (COVID‐19) in China. However, risk factors associated with occurrence of COVID‐19 among close contacts have not been well described. 106 household contacts were included in this study, of whom 19 were developed into COVID‐19 cases and the secondary attack rate was 17.9%. Multivariable analysis showed increasing risk of occurrence of COVID‐19 among household contacts associated with female of index patients (Adjusted Hazard Ratio [aHR] = 3.84, 95%CI = 1.07‐13.78), critical disease of index patients ([aHR] = 7.58, 95%CI = 1.66‐34.66), effective contact duration with index patients >2 days ([aHR] = 4.21, 95%CI = 1.29‐13.73), and effective contact duration >11 days ([aHR] = 17.88, 95%CI = 3.26‐98.01).The sex and disease severity of index COVID‐19 patients, and longer effective contact duration with COVID‐19 confirmed cases could help epidemiologists to identify potential COVID‐19 case among household contacts at an early stage.