ABSTRACT
Objective@#To report an investigation of a family cluster of coronavirus disease 2019 ( COVID-19 ) in Ningbo, so as to provide reference for the prevention and control measures.@*Methods@#According to the COVID-19 Prevention and Control Program ( fourth version ) , an epidemiological investigation was conducted to collect the demographic information, clinical features and exposure history, to find the close contacts, and to figure out the source and route of infection. @*Results@#Twelve confirmed cases and one asymptomatic case were reported. The attack rate was 16.05%. Among them, five were males and eight were females; the age ranged from 11 to 85 years old, with a median of 39 years old; most had mild symptoms. The incubation period was 2-13 days, with a median of 6.5 days. The first case ( Case 1 ) developed the symptoms on January 22, and had close contact with Zhang, an asymptomatic case, on January 20. Zhang was related to a cluster in the Buddhist assembly on January 19. Case 1, who caused the spread of the epidemic among family members, participated in several family visits and dinners from January 22 to 27 with other 24 families, resulting in six secondary cases and six third-generation cases. There were 54 close contacts except the family members, no infection was found. @*Conclusion@#This family cluster may result from the close contact with an asymptomatic case, and then spread within families through having dinners and living together.
ABSTRACT
Objective@#To analyze the epidemiological characteristics of coronavirus disease 2019 （COVID-19） cases reported in Ningbo from January 22 to February 22, 2020, so as to provide guidance for the prevention and control of the COVID-19 epidemic.@*Methods@#The confirmed cases of COVID-19 reported by Ningbo were selected from National Diseases Prevention and Control Information System to analyze the epidemiological characteristics by descriptive epidemiological method, including time, spatial and population distribution, clinical symptoms and exposure history.@*Results@#A total of 157 confirmed cases of COVID-19 were reported and there was no death. The first confirmed case was reported on January 22. On the incidence curve, the peak was from January 22 to February 4, with a maximum of 15 cases in a single day. The incidence curve presented sustained human-to-human transmission. The number of the cases showed a declining trend from February 5. The confirmed cases were reported in all 10 counties（cities or districts）,among which 69（43.95%）cases were reported in Haishu District. The confirmed cases were mainly 30-69 years old,accounting for 78.34%;were mainly farmers,household workers and retired people,accounting for 59.87%;and were mainly clinically mild,accounting for 87.90%.There were 51 imported cases, accounting for 32.48%. The initial confirmed case was a local case. In the early stage of the epidemic, local cases and imported cases prevalent together,which was due to the outbreak caused by the large-scale buddhist activity on January 19.This event resulted in 67 confirmed cases and 15 asymptomatic cases. There totally reported 22 clusters with 138 （87.90%）confirmed cases. @*Conclusions@# In the early stage of the COVID-19 epidemic in Ningbo, the imported cases and local cases prevalent at the same time. Most of the cases were female, aged from 30 to 69 years, and their occupation were farmers, household workers and retired people. With comprehensive measures taken, the epidemic of COVID-19 in Ningbo have been under control.