Clin Exp Vaccine Res.  2022 Jan;11(1):96-103. 10.7774/cevr.2022.11.1.96.

Large inter-individual variability of cellular and humoral immunological responses to mRNA-1273 (Moderna) vaccination against SARS-CoV-2 in health care workers

• Krüttgen A
• Haase G
• Haefner H
• Imöhl M
• Kleines M

• KMID: 2534932
• DOI: http://doi.org/10.7774/cevr.2022.11.1.96

Abstract

Purpose
Studies on the immune responses to severe acute respiratory syndrome coronavirus 2 vaccines are necessary to evaluate the ongoing vaccination programs by correlating serological response data and clinical effectiveness data. We performed a longitudinal immunological profiling of health care workers vaccinated with mRNA-1273 (Moderna, Cambridge, MA, USA). Half of these vaccinees had experienced a mild coronavirus disease 2019 (COVID-19) infection in the spring of 2020 (“COVID-recovered” cohort), whereas the other half of the vaccinees had no previous COVID-19 infection (“COVID-naive” cohort).
Materials and Methods
Serum was drawn at multiple time points and subjected to assays measuring anti-Spike immunoglobulin G (IgG), avidity of anti-Spike IgG, avidity of anti-receptor binding domain (RBD) IgG, virus neutralizing activity, and interferon-γ release from stimulated lymphocytes.
Results
Between both cohorts and within each cohort, we found remarkable inter-individual differences regarding cellular and humoral immune responses to the Moderna mRNA-1273 vaccine.
Conclusion
First, our study indicates that the success of mRNA-1273 vaccinations should be verified by serological assays in order to identify “low-responders” to vaccination. Second, the kinetics of anti-S IgG and neutralizing activity correlate well with clinical effectiveness data, thus explaining incipient protection against infection 2 weeks after the first dose of mRNA-1273 in COVID-naive vaccinees. Third, our IgG-avidity data indicate that this incipient protection is mediated by low-avidity anti-RBD IgG and low-avidity anti-S IgG.

Keyword

COVID-19; Non-responders; Vaccination; Avidity; SARS-CoV-2