Delayed Antibody and T-Cell Response to BNT162b2 Vaccination in the Elderly, Germany

Abstract

We detected delayed and reduced antibody and T-cell responses after BNT162b2 vaccination in 71 elderly persons (median age 81 years) compared with 123 healthcare workers (median age 34 years) in Germany. These data emphasize that nonpharmaceutical interventions for coronavirus disease remain crucial and that additional immunizations for the elderly might become necessary.

Keywords: B cell; Berlin; COVID-19; Germany; SARS-CoV-2; T cell; antibody; coronavirus disease; immunity; mRNA; respiratory infections; severe acute respiratory syndrome coronavirus 2; vaccine; viruses; zoonoses.

Figure

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific antibody and T-cell response after vaccination with BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) in the elderly, Germany. A) SARS-CoV-2 RBD IgG measured in serum of BNT162b2-vaccinated younger participants (healthcare workers) before the first vaccination (n = 100, week 0), 3 weeks after the first vaccination (n = 107, week 3), and 4 weeks after the second vaccination (n = 113, week 7) and from elderly participants at week 0 (n = 70), week 3 (n = 52), and week 7 (n = 70) using the SeraSpot Anti-SARS-CoV-2 IgG assay (Seramun Diagnostica GmbH, https://www.seramun.com). B) Neutralizing capacity of antibodies measured at week 3 and 7 in the young and elderly cohorts using the ELISA-based surrogate virus neutralization test (sVNT) cPass (medac GmbH, https://international.medac.de). C) SARS-CoV-2 spike IgG avidity analyzed in the healthcare workers cohort (n = 30) and elderly cohort (n = 16) at week 3 and 7. D) At week 7, whole blood from vaccinated elderly participants (n = 43) and young participants (n = 71) was stimulated ex vivo with components of the S1 domain of the spike protein for 24 h, and IFN-γ concentration in the supernatant was detected by ELISA. Dotted lines indicate the manufacturer’s specified threshold for RBD IgG >1 S/Co, for sVNT >30%, and for avidity 40–60% borderline avidity and >60% high avidity. For IGRA, we defined an arbitrary threshold at 334.2 mIU/mL. p value was calculated by the nonparametric Mann Whitney U test, and the median and interquartile range are depicted. ACE2, angiotensin-converting enzyme 2; IFN-γ, interferon-γ; IU, international units; NS, not significant; RBD, receptor-binding domain; S/CO, signal-to-cutoff ratio; sVNT, surrogate virus neutralization test.