At the start of this study, phase 1 clinical trial data was not yet available; thus, the sample size was determined based on minimum requirements outlined by the National Medical Products Administration of China and expert opinion. Power calculations were performed using PASS software once phase 1 data became accessible, confirming a power of at least 90%. Correlation analysis was conducted for specific and neutralizing antibodies to calculate a Pearson correlation coefficient. ANOVA was used for log-transformed antibody titers, the Wilcoxon rank-sum test for non-normally distributed data, and Fisher's exact test for categorical data.