ABSTRACT
Objective@#To explore the features of close contacts of coronavirus disease 2019 ( COVID-19 ) cases in Jiulongpo District, Chongqing, so as to provide evidence for the management of close contacts and the control of the epidemic.@*Methods@#Demographic characteristics, contact history and medical records of close contacts of COVID-19 cases in Jiulongpo District from January 22 to April 10, 2020 was collected according to the COVID-19 Prevention and Control Program ( sixth version ) . Descriptive statistical analysis was performed.@*Results@#Totally 602 close contacts were found, and 30 of them were infected, with an attack rate of 4.98%. Twenty-seven cases were diagnosed before February 10. The close contacts mainly aged from 20 to 59 years ( 457, 75.91% ) ; most were relatives of COVID-19 cases ( 219, 36.38% ) , and 64 (10.63%) were medical staff. Most contacted occasionally ( 338, 56.15% ), at home ( 190, 31.56% ) , and through the same meal ( 181, 30.07% ) . The attack rate of close contacts aged 40 years and over was 7.49%, which was higher than 2.37% of those aged under 40 years ( P<0.05 ). The attack rate of close contacts increased with contact frequency ( P<0.05 ) . The attack rates of close contacts were significantly different in different relations with cases, contact places and contact modes ( P<0.05 ); the attack rates of colleagues and relatives were 20.41% and 8.68%; the attack rates of close contacts in the workplace settings and family were 17.54% and 10.00%; the attack rates of sharing the same bed, living in the same room and working in the same room were 44.44%, 18.60% and 17.24%.@*Conclusions @#The close contacts of COVID-19 cases in Jiulongpo District, Chongqing who aged 40 years or above, exposed in family settings and in the workplace were associated with higher risk of infection.