Background: Humoral responses after SARS-CoV-2 vaccination are greatly impaired in multiple sclerosis (MS) patients on fingolimod. Effects of repeated vaccination and infections on long-term responses are unclear.
Methods: Prospective study in 60 MS patients on fingolimod measuring humoral responses after up to four vaccinations and 8 months after fourth vaccination.
Results: Anti-WH1 antibody titers increased with each additional vaccination. At long-term follow-up titers increased further and most patients developed new humoral responses against the BA.1 omicron variant.
Conclusion: Repeated SARS-CoV-2 vaccinations boost humoral immunity and, probably together with SARS-CoV-2 infections, induce humoral responses on the long-term in almost all patients.
Keywords: COVID-19; S1P modulators; antibodies; immunization; omicron.