Figure 1.

(a) SARS-CoV-2-S1 IgG levels in two, three, and four times vaccinated anti-CD20-treated pwMS and three times vaccinated HC were measured by ELISA. pwMS sampled more than once are connected by lines. The dotted horizontal line indicates the manufacturer’s threshold of an SARS-CoV-2-S1 IgG OD ratio of 1.1, levels above which were considered positive. (b) Relative avidity indices in anti-S1 IgG reactive (Ab reactive) two, three, and four times vaccinated anti-CD20-treated pwMS and three times vaccinated HC. pwMS sampled more than once are connected by lines. The dotted horizontal line indicates a relative avidity index of 60, levels equal to or above which were considered high. (c) Serum neutralization titers against Omicron BA.2 were analyzed in two, three, and four times vaccinated pwMS and three times vaccinated HC. Serum dilutions with a plaque reduction of 90% are referred to as PRNT90 titers. PRNT90 titers ⩾ 20 were considered to indicate the presence of neutralizing antibodies. (d) Whole blood of pwMS vaccinated two, three, or four times and of HC vaccinated three times against SARS-CoV-2 was stimulated ex vivo with components of the S1 domain of the spike protein for 24 hours, and interferon (IFN)-γ concentration in the supernatant was measured by ELISA. The dotted horizontal line indicates IFN-γ concentrations of 200 mIU/mL, levels above which indicate the presence of SARS-CoV-2-specific T cells. The pwMS with a very low T-cell response following three vaccinations had an additional combined immunodeficiency syndrome. (a, b, d) p-values were calculated by a linear mixed model with Bonferroni correction.

HC: healthy controls; IFN-γ: interferon-γ; IgG: immunoglobulin G; IGRA: interferon-γ release assay; IU: international units; ns: not significant; OD: optical density; PRNT: plaque reduction neutralization test; S: SARS-CoV-2 spike protein S1 domain; vac: vaccination.