Study on transmission dynamic of 15 clusters of COVID-2019 cases in Ningbo
10.3760/cma.j.cn112338-20200330-00466
- VernacularTitle:宁波市15起新型冠状病毒肺炎聚集性疫情的传播力研究
- Author:
Xingqiang PAN
1
;
Yi CHEN
;
Aihong WANG
;
Jianmei WANG
;
Lixia YE
;
Shaohua GU
;
Ting FANG
;
Guozhang XU
Author Information
1. 宁波市疾病预防控制中心 315010
- Keywords:
COVID-19;
Generation time;
Basic regeneration number;
Cluster
- From:
Chinese Journal of Epidemiology
2020;41(12):2010-2014
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To describe the basic characteristics of clusters of coronavirus diseases 2019 (COVID-19) cases in Ningbo, Zhejiang province, and evaluate the generation time (Tg) and basic reproduction number ( R0) of COVID-19. Methods:The basic information and onset times of the clusters of COVID-19 cases in Ningbo were investigated, the inter-generational interval of the cases were fitted by using gamma distribution, and the R0 was calculated based on the SEIR model. Results:In the 15 clusters of COVID-19 cases, a total of 52 confirmed cases, 5 cases of nucleic acid-positive asymptomatic cases. The cases occurred from January 23 to February 4, the cases were mainly women. The incubation period was (6.11±3.38) days, and the median was 5 days. The Tg was (6.93±3.70) days. There were no significant differences in Tg between age group<60 years and age group 60 years and above, and between men and women ( P=0.551). According to the Tg calculated in this paper, the R0 of COVID-19 in Ningbo was 3.06 (95 %CI: 2.64- 3.51); according to the reported case transmission interval of 7.5 days in the literature, the R0 was 3.32 (95 %CI: 2.51-9.38). Conclusion:There is no age and gender specific differences in the Tg of clusters of COVID-19 cases in Ningbo, and COVID-19 has high infectivity and spreading power in early phase.
