Fig. 1.

Study design to determine humoral immune responses to BNT162b2 vaccination in health care workers in a longitudinal observational study. In total, 60 participants were included in this study. Anti-S1 IgG and surrogate neutralizing antibodies were determined at five different time points (t1–t5). A bead-based analysis of antibodies against different SARS-CoV-2 target epitopes and a live virus neutralization assay to determine neutralization against wild-type and the B.1.617.2 (delta) variant of concern were performed in a representative subgroup analysis 3 weeks (t2) and 7 months (t5) after second vaccination. IQR, interquartile range.