Drulovic, Jelena (55886929900)Jelena (55886929900)DrulovicIvanovic, Jovana (57196371316)Jovana (57196371316)IvanovicMartinovic, Vanja (56925159700)Vanja (56925159700)MartinovicTamas, Olivera (57202112475)Olivera (57202112475)TamasVeselinovic, Nikola (57206405743)Nikola (57206405743)VeselinovicCujic, Danica (35796937900)Danica (35796937900)CujicGnjatovic, Marija (57192211847)Marija (57192211847)GnjatovicMesaros, Sarlota (7004307592)Sarlota (7004307592)MesarosPekmezovic, Tatjana (7003989932)Tatjana (7003989932)Pekmezovic2025-07-022025-07-022021https://doi.org/10.1016/j.msard.2021.103150https://www.scopus.com/inward/record.uri?eid=2-s2.0-85110595670&doi=10.1016%2fj.msard.2021.103150&partnerID=40&md5=2cbb7b2c41b1b4ca4a72d65069c43a90https://remedy.med.bg.ac.rs/handle/123456789/12320Background: It has been generally accepted that people with MS (PwMS) should be vaccinated against COVID-19. The aim of our investigation was to evaluate the humoral response to natural SARS-CoV-2 infection and to two COVID-19 vaccines (BNT162b2 Pfizer-BioNTech and Beijing/Sinopharm BBIBP-CorV) in our cohort of PwMS under high efficacy disease modifying therapies (DMTs), cladribine and alemtuzumab. Methods: Twenty two PwMS treated at the Clinic of Neurology, in Belgrade, who developed COVID-19 and/or were vaccinated against SARS-CoV-2, during treatment with cladribine and alemtuzumab, were included. Out of 18 patients treated with cladribine, 11 developed COVID-19, and 11 were vaccinated against SARS-CoV-2 (four with mRNA vaccine, 7 with Sinopharm). Four MS patients under alemtuzumab were vaccinated against SARS-CoV-2; three with mRNA, and one with Sinopharm vaccine. SARS-Cov-2 IgG response was measured using ELISA anti-spike protein-based serology (INEP, Belgrade, Serbia). Results: All 7 patients under cladribine treatment who suffered from COVID-19, developed IgG antibodies, 2.0-5.5 months after last symptoms. All four (100%) patients under cladribine who were vaccinated with Pfizer-BioNTech vaccine, and three out of seven (42.9%) vaccinated with Sinopharm, developed antibodies. All 4 patients under alemtuzumab developed antibodies after vaccination. In all cases, seroprotection occurred, irrespective of timing of vaccination and absolute lymphocyte count. Conclusion: Our findings in a small number of highly active PwMS in whom, lymphodepleting, immune reconstitution therapies, were applied in order to successfully manage MS, indicate that in a number of these patients it was possible to develop at the same time seroprotection in these patients after COVID-19 vaccination in these complex circumstances. © 2021 The Author(s)alemtuzumabcladribineCOVID-19humoral responsemultiple sclerosisPfizer-BioNTechSinopharmvaccination