At the start of this study phase 1 clinical trial data was not yet available and thus the sample size of this experiment was determined based on the minimum requirement as outlined by the National Medical Products Administration of China and expert opinion. Power calculations were done once phase one data was assessible via PASS software to determine if the chosen group sizes were acceptable for the study and it was found to provide a power of at least 90%. Correlation analysis was done for the specific and neutralizing antibodies to calculate a Pearson correlation coefficient. ANOVA was done for long transformed antibody titers, the Wilcoxon rank sum test for abnormal data, and Fisher's exact test for categorical data.