Soaring Asymptomatic Infected Individuals Bring About Barriers and Difficulties for Interruption of COVID-19 Prevalence in China.

Background: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic, which has caused unprecedented damage to human health and life. The present study aimed to carry out and discover asymptomatic infected individuals in Shenzhen, China. The data will provide the control measures to stop COVID-19 prevalence. Methods: The study was a retrospective review of medical records from 462 confirmed patients with COVID-19 and 45 asymptomatic infected individuals in Shenzhen from January 19 to April 30, 2020; this is a retrospective, observational multicenter study. Results: A total of 462 confirmed cases were diagnosed in Shenzhen from January 19 to April 30, 2020. The cohort included 423 domestic cases (91.56%, 95% confidence interval [CI]: 88.67-93.76) and 39 (8.44%, 95% CI: 6.24-11.33) imported cases from other countries. Moreover, a total of 45 asymptomatic infections were found, encompassing 31 (68.89%, 95% CI: 54.34-80.47) local infections and 14 (31.11%, 95% CI: 19.53-45.66) individuals imported from other countries. The proportion of asymptomatic infected persons in Shenzhen is continuously increasing (Z = 13.19, p < 0.0001). The total number of local asymptomatic infections was more than that in other provinces (χ2 = 118.83, p < 0.0001). The proportion of asymptomatic infected individuals among cases imported from other countries was higher than the domestic cases (χ2 = 22.51, p < 0.0001, odds ratio = 4.90, 95% CI: 2.40-9.98). Conclusions: The proportion of asymptomatic infection is increasing. Hence, development and application of the diagnosis method with high sensitivity and specificity play a critical role in reducing COVID-19 global epidemics.