Statistical analysis
SECONDARY, REMISSION, SARS-COV-2 INFECTION, DISEASE
The sample size in this clinical trial was determined on the basis of statistical power calculations. We proposed greater than 90% power to detect a 20% relative difference between the A8G6 treated and control group at a two-sided alpha level of 0.05 (ie., a 20% prevention efficacy of A8G6). The formula is as follows:which The primary efficacy endpoints including COVID-19 incidence and time to confirmed SARS-CoV-2 infection. The COVID-19 incidence was analyzed using the Kaplan–Meier method and log-rank test, and the time to confirmed SARS-CoV-2 infection was analyzed using Wilcoxon rank-sum test. The secondary efficacy endpoints including viral load when confirmed SARS-CoV-2 infection and the time to negative conversion of SARS-CoV-2 determined by RT-PCR. The viral load when confirmed SARS-CoV-2 infection was analyzed using Wilcoxon rank-sum test, negative conversion of SARS-CoV-2 and remission time were conducted using Kaplan–Meier method and log-rank-test. Safety was assessed in participants in the full analysis set who received A8G6 nasal spray treatment during the 8-day quarantine period.Database from the Service Platform for COVID-19 Prevention and Control created by Yuzhong District Center for Disease Control and Prevention were authorized for us to use and analyze. Data including demographic and clinical characteristics of the cohorts, endpoints in this clinical trial were collected from an applet of WeChat (a social media platform in China), called “Yuzhong Information Exchange”. All data were summarized with descriptive statistics (number of subjects (%), median (IQR), mean ± sd). The credible interval for nasal spray was calculated with the use of a beta-binomial model with prior beta (1, 1) adjusted for the treatment duration time. Continuous variables were compared with the Mann–Whitney U-test, and Categorical variables were conducted using χ2 test or Fisher’s exact test. A 