Health-care workers were enrolled at Charité-Universitätsmedizin Berlin (n= 107) and older people were enrolled at an assisted living facility in Berlin, Germany (n= 82).(A) Anti-S1 IgG in serum measured by a microarray-based immunoassay.(B) Serum neutralisation titres (serum ID50) against the delta (B. 1.617. 2) VOC were measured 4 weeks after completion of the two-dose vaccine regimen with BNT162b2, and at the 6-month follow-up using a pseudovirus neutralisation assay.(C) SARS-CoV-2 S1-specific T-cell response detected by inteferon-γ release assay. Dotted horizontal lines indicate the manufacturer’s threshold such as that for anti-S1 IgG≥ 1 S/Co (A) and the lower limit of detection (1: 10 dilution) for pNT (B). Horizontal lines within plotted data regions indicate the median and IQR, except for pNT, for which the geometric mean and 95% CI is shown. P values (all less than 0· 0001) were calculated by the non-parametric Mann Whitney U test. ID50= 50% inhibition dilution. IU= international units. pNT= pseudovirus neutralisation test. S/Co= signal-to-cutoff ratio. VOC= variant of concern.