Statistical analysis

Descriptive statistics were calculated using GraphPad Prism 8.4.3. All data points represent biological replicates for each group. Each immunologic assay was performed for each sample independently without technical replicates. Data are presented as median with interquartile range (IQR). Comparisons were performed using the Wilcoxon rank-sum test. Spearman correlation coefficient (r) was reported for antibody titers with time from first vaccine dose and age. All tests were two-tailed. When all six variants were compared between infected and uninfected or between BNT162b2 and mRNA-1273, a p value < 0.01 was considered statistically significant to account for multiple comparisons. For all other comparisons, p values < 0.05 were considered statistically significant.