ABSTRACT
Objective To describe features of central nervous system (CNS) demyelinating events following vaccination against coronavirus disease 19 (COVID- 19). Background Several reports suggest a potential association between COVID-19 vaccines and acute CNS inflammation. Design/Methods A case series was performed at the BARLO MS Centre in Toronto, Ontario, Canada. Clinicians reported patients who experienced an acute CNS demyelinating event within 60 days after receiving at least one COVID-19 vaccination from March 2021 to January 2022. Clinical characteristics were evaluated. Results Twenty patients were identified (median age 39 years (range 25-82);13 (65.0%) female). Two had pre-existing multiple sclerosis (MS). Individuals received the Pfizer (n = 14), Moderna (n = 5) or Astrazeneca (n = 1) COVID-19 vaccines. Within 1-53 days (median 12) of the first (n = 8) or second (n = 12) vaccine dose, patients developed transverse myelitis (TM) (n = 15), optic neuritis (n = 4) or brain demyelination (n = 4). Diagnoses at last follow up (median 114 days (range 39-255)) were relapsing remitting MS (n = 8), post-vaccine TM (n = 5), clinically isolated syndrome (n = 3), myelin oligodendrocyte glycoprotein antibody disease (n = 2), MS relapse (n = 1) and neuromyelitis optica spectrum disorder (n = 1). Thirteen patients received pulse corticosteroids, and of these, 4 received plasma exchange. Seven did not receive acute treatment. 20.0% returned to baseline (n = 4), 75.0% partially recovered (n = 15) and 5.0% worsened (n = 1). At last follow up, 11 were on disease modifying therapy and 9 were not. Nine patients received a subsequent COVID-19 vaccine. Of these, one experienced symptom recrudescence without radiologic evidence of a new demyelinating attack. Conclusions To our knowledge, this is the largest series to date describing acute CNS demyelination after vaccination against COVID-19. The rate of vaccination in the eligible general population was high during the time of the cases and we could not determine whether the number of demyelinating events was higher than expected. Repeat vaccination was not associated with recurrent adverse events in this small observational series.