New diagnosis of multiple sclerosis in the setting of recent Sinopharm COVID-19 vaccine (BBIBP-CorV) exposure: A series of clinical cases and updated review of the literature

<b>Background:</b> Multiple sclerosis (MS) is the most common cause of non-traumatic disability in young individuals. There are limited reports of developing demyelinating events following the coronavirus disease 2019 (COVID-19) vaccination. <b>Methods:</b> We reported all individuals (n = 8) with new MS diagnoses with recent exposure (≤ 6 weeks) to the Sinopharm (BBIBP-CorV) vaccine between September 2021 and June 2022. We also reviewed the related literature published as of September 2023. <b>Results:</b> Of 338 newly diagnosed patients with MS who attended our tertiary referral MS center during the study period, 8 (2.36%) had their first demyelinating attack with a median interval of 2 [2.0, 4.0] weeks following the Sinopharm vaccine (sex ratio 1:1, median age: 20.5 [18.0, 27.0] years). No personal or family history of autoimmune/neurological disorders was documented, except for one patient's history of a previous potential demyelinating event and another's family history of immune thrombocytopenic purpura (ITP). All patients had demyelinating brain MRI lesions, and 4 had cervical spinal cord involvement. The brain areas most commonly affected were the periventricular and subcortical regions. Positive oligoclonal bands (OCBs) in all patients supported the MS diagnosis. All patients were diagnosed with relapsing-remitting MS and received intravenous methylprednisolone (IVMP) alone or in combination with plasma exchange (3/8). Rituximab was the most frequently used disease-modifying treatment (3/8). <b>Conclusion:</b> This study provides preliminary evidence of a potential association between the Sinopharm vaccine and the initial manifestations of MS. However, further larger-scale studies with control groups and long-term follow-ups are needed to confirm this association and determine the underlying mechanisms.