Serological response to SARS-CoV-2 vaccination in multiple sclerosis patients treated with fingolimod or ocrelizumab: an initial real-life experience

Background: Recent observations suggest a lack of humoral response after SARS-CoV-2 vaccination in multiple sclerosis (MS) patients treated with fingolimod or ocrelizumab Objectives: To assess serological response to SARS-CoV-2 vaccination in MS patients receiving these disease-modifying treatments (DMTs) in a real-life setting. Methods: Retrospective clinical data collection from MS patients followed at San Raffaele Hospital MS Centre (Milan, Italy). All patients treated with fingolimod or ocrelizumab who had received a complete anti-COVID-19 vaccination course, with no clinical history suggestive of previous SARS-CoV-2 infection and with an available post-vaccination serological assay obtained at least 14 days after vaccination completion were considered for the study. Results: We collected data from 32 MS patients, 16 treated with fingolimod and 16 receiving ocrelizumab. Among the fingolimod group 10 patients (62.5%) had a positive serological response after vaccination and among ocrelizumab-treated patients a positive serological test was found in six cases (37.5%). No relation between serological response and clinical features (i.e., treatment duration, time between vaccination and last treatment dose, and white blood cells count) was identified. Conclusions: Our initial real-life experience suggests a variable antibody production in MS patients receiving these DMTs. At present, there are no sufficient data to do not recommend anti-SARS-CoV-2 vaccine in these patients.