Immunogenicity of Hepatitis B Virus Vaccination in Relapsing-Remitting Multiple Sclerosis Patients Under Immunocompromising Treatment.

Multiple sclerosis (MS) is an autoimmune and demyelinating disease of the central nervous system (CNS). By acting on the immune system, disease-modifying therapies (DMTs) can control disease activity, but they indirectly increase susceptibility to infections, so different vaccines are necessary to prevent it. DMTs may potentially affect vaccine-induced seroconversion. We aim to analyse the response to the hepatitis B virus (HBV) vaccine (Engerix-B) in relapsing-remitting MS patients (RRMS) using these therapies because the scientific literature remains limited in this area. A retrospective observational study of RRMS patients vaccinated against HBV was conducted. Acquired immunity after vaccination was determined, and an analysis of immunogenicity was conducted based on the type of DMT (immunomodulators/immunosuppressants), vaccine doses, total lymphocyte count (TLC), age, and sex. 200 patients were included, with a mean age 47.79 years, and 140 (70%) were women. A lower vaccine response was observed in patients treated with immunosuppressive DMTs (51.8%, p < 0.001), particularly with fingolimod (32.4%, p < 0.001), and a higher response was seen with immunomodulators like teriflunomide and interferon-β1a (100%, p < 0.001). Using logistic regression, a model was obtained that included the number of vaccine cycles, lymphopenia and type of DMT associated with the response to the HBV vaccine. It is necessary to adapt HBV vaccination protocols for MS patients, considering the type of DMT used and baseline immune status.