Response to COVID-19 Epidemic
Epidemiological characteristics of imported COVID-19 cases in Beijing
Dong Shuaibing, Wang Xiaoli, Zhao Hao, Wang Yu, Liu Baiwei, Liu Yonghong, Pan Yang, Jia Lei, Wang Quanyi, Yang Peng
Published 2022-04-10
Cite as Chin J Epidemiol, 2022, 43(4): 478-482. DOI: 10.3760/cma.j.cn112338-20211213-00975
Abstract
ObjectiveTo analyze the epidemiological characteristics of imported COVID-19 cases and the effect of vaccination on virus load and disease severity of the cases in Beijing.
MethodsThe data of the imported COVID-19 cases in Beijing were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and Epidemiology investigation. The data were processed and analyzed by Excel 2010 and SPSS 22.0.
ResultsFrom June 1 to September 30, 2021, a total of 171 imported COVID-19 cases were reported in Beijing, of which 66.67% (114/171) were asymptomatic. The cases were mainly from the Philippines, the United Arab Emirates, the United Kingdom and the Russian Federation, accounting for 67.84% (116/171). The male to female ratio of the cases was 2∶1 (114∶57). The median age M (Q1, Q3) of the cases was 28 (23, 36) years. The cases of Chinese accounted for 80.12% (137/171). The sequencing of the whole genome of the virus in 47 imported COVID-19 cases showed that the proportion of Delta variant was 76.60% (36/47). The COVID-19 vaccination coverage rate in the cases was 60.82% (104/171), but the full vaccination coverage rate was 53.80% (92/171). In the imported COVID-19 cases, 13.53% (23/170) were screened to be SARS-CoV-2 nucleic acid positive on the day when they arrived in Beijing, and all the cases were positive for 2019-nCoV nucleic acid within 28 days. The severity of the disease was higher in the unvaccinated group than in the partially vaccinated group and fully vaccinated group (P<0.001). In the unvaccinated group, there were 1 severe case and 1 critical case. The median Ct values M (Q1, Q3) of N gene and ORFlab gene in unvaccinated group were 32.51 (23.23, 36.06) and 32.78 (24.00, 36.38), respectively. There was no significant difference in the median of double-gene Ct value between the partially vaccinated group and the fully vaccinated group.
ConclusionsDuring the study period, most of the imported COVID-19 cases in Beijing were asymptomatic. No matter vaccinated or not, the viral loads in the COVID-19 cases were similar, but the vaccination could reduce the severity of the disease.
Key words:
COVID-19; Imported case; Epidemiological characteristics
Contributor Information
Dong Shuaibing
Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Wang Xiaoli
Office of Beijing Center for Global Health, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Zhao Hao
Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Wang Yu
Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Liu Baiwei
Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Liu Yonghong
Office of Beijing Center for Global Health, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Pan Yang
Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Jia Lei
Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Wang Quanyi
Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing 100013, China
Yang Peng
Office of Beijing Center for Global Health, Beijing Center for Disease Prevention and Control, Beijing 100013, China
