Achtnichts, LutzLutzAchtnichtsOvchinnikov, ArkadyArkadyOvchinnikovJakopp, BarbaraBarbaraJakoppOberle, MichaelMichaelOberleNedeltchev, KrassenKrassenNedeltchevFux, Christoph AndreasChristoph AndreasFuxSellner, JohannJohannSellnerFindling, OliverOliverFindling2024-10-092024-10-092022-02-21https://boris-portal.unibe.ch/handle/20.500.12422/67904Evidence suggests limited development of protective IgG responses to mRNA-based vaccines in sphingosine-1-phosphate receptor (S1PR)-modulator treated individuals with multiple sclerosis (MS). We studied the extent of the humoral immune response after the preferred third mRNA SARS-CoV-2 vaccine in S1PR-modulator treated people with MS (pwMS) and insufficient IgG responses after the standard immunization scheme. Eight pwMS that were treated with fingolimod received a third homologous SARS-CoV-2 mRNA vaccine dose, either the Moderna's mRNA-1273 or Pfizer-BioNTech's BNT162b2 vaccine. We quantified the serum levels of IgG antibodies against the receptor-binding domain of SARS-CoV-2 four weeks later. An antibody titer of 100 AU/mL or more was considered protective. After the third vaccination, we found clinically relevant IgG titers in four out of eight individuals (50%). We conclude that the humoral immune response may reach protective levels after the third preferred dose of the homologous SARS-CoV-2 mRNA vaccine. Vaccine shots in S1PR-modulator treated pwMS ahead of schedule may be a strategy to overcome insufficient humoral immune responses following the standard vaccination scheme.enCOVID-19 S1PR-modulator SARS-CoV-2 fingolimod humoral immune response vaccination600 - Technology::610 - Medicine & healtharticle10.48350/1661253521479910.3390/vaccines10020341