The Impact of Disease-Modifying Therapies of Multiple Sclerosis on the Effectiveness of the BBIBP-CorV COVID-19 Vaccine

Background: It is well-known that disease-modifying therapies (DMTs) in patients with multiple sclerosis (PwMS) may reducethe immune response to COVID-19 vaccines. Objectives: The present study aimed to investigate the efficacy of the Sinopharm/BBIBP-CorV vaccine in Iranian PwMS treatedwith different DMTs. Methods: This quasi-experimental study was conducted between January 2021 and January 2022 at the MS clinics of ImamHossein and Qaem Hospitals in Tehran and Mashhad, Iran. Based on inclusion and exclusion criteria, PwMS received two dosesof the Sinopharm vaccine at an interval of 28 days. The humoral response to the vaccine was evaluated by measuring the IgGreceptor-binding domain (RBD-IgG) against SARS-CoV-2 on three occasions: before vaccination, 28 days after the first dose, and28 days after the second dose. Results: Of the 208 patients, 117 were eligible for analysis. The Sinopharm vaccine was generally safe among Iranian PwMS. TheIgG antibody titer against the SARS-CoV-2 strain was significantly associated with the DMT class. Patients treated withfingolimod and rituximab developed the lowest humoral response to the Sinopharm vaccine (21.1% and 38.4%, respectively). Conclusions: The present study revealed that PwMS treated with fingolimod and rituximab are likely to have a suboptimalhumoral response to the Sinopharm vaccine. This finding may help neurologists make informed decisions about DMT selectionduring the pandemic