Abstract：Objective To analyze the infectivity of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients in Chenzhou City, and to provide a basis for formulating epidemic prevention and control strategies. Methods The characteristics of asymptomatic patients infected with SARS-CoV-2 and the infection situation of their close contacts in Chenzhou City were tracked. Real-time quantitative fluorescence (RT-PCR) method was used to detectSARS-CoV-2 nucleic acid. Colloidal gold method was employed to detect SARS-COV-2 antibody in serum, and infectivity analysis was performed. Results Ten cases of asymptomatic infection were followed up, of which 5 cases were diagnosed as confirmed cases, namely, patients with pre-symptomatic infection, and 5 cases were persistently asymptomatic, namely, patients with latent infection. There was a statistically significant difference in the average age between the patients with latent infection and the patients with pre-symptomatic infection (P=0.037). Time distribution revealed that pre-symptomatic infection was the main infection in the early stage of the epidemic, while latent infection was the main infection in the middle and late stages. The sources of exposure displayed that family life exposure wasthe most common. Chest CT of the 5 patients with pre-symptomatic infection showed typical imaging findings of COVID-19, but only 3 patients presented with mild clinical symptoms. A total of 264 close contacts of the asymptomatic infected patients were tracked, including 108 contacts who had been in close contact with only one asymptomatic infected patient based on the 5 pre-symptomatic infection patients. The detection showed that 4 cases were positive for COVID-19 nucleic acid and 5 cases positive for antibody. There were 38 contacts who had been in close contact with only one asymptomatic infected patient based on the 5 latent infection patients. The detection showed that COVID-19 nucleic acid and antibody were both negative. There were 118 contacts who had been in close contact with ≥ 2 infected patients based on the pre-symptomatic and latent infection patients, and 12 contacts were positive for nucleic acid and antibody. Conclusion There are asymptomatic infections in the patients infected with SARS-CoV-2, and the pre-symptomatic infection is infectious. This study indicates that the latent infection is not infectious, but it needs to be further verified. The results suggest that nucleic acid and CT examinations should be carried out simultaneously in the early stage so as to detect asymptomatic infection as soon as possible.
谭晓罗, 刘勋, 谭文艳, 谭徽, 李映霞, 陈柏塘, 朱韩武, 刘卫. 郴州市10例新冠肺炎无症状感染者的传染性分析[J]. 实用预防医学, 2022, 29(6): 702-705.
TAN Xiao-luo, LIU Xun, TAN Wen-yan, TAN Hui, LI Ying-xia, CHEN Bai-tang, ZHU Han-wu, LIU Wei. Infectivity of 10 asymptomatic patients with COVID-19 infection in Chenzhou City. , 2022, 29(6): 702-705.
2022, Vol. 29 
