Convalescent plasma in patients receiving Rituximab or Ocrelizumab for Multiple Sclerosis or Neuromyelitis Optica Spectrum Disorder with COVID-19: A Multicenter Retrospective Study

•Overall 30-day survival after CCP was 97% [IC95%: 91-99]).•Protracted COVID-19 persisted for 51 [28-69] days (184 days maximum) before CCP.•Fever resolved in all patients with protracted COVID-19 seven days after CCP.•Clinical improvement was 98% at day 30 after CCP in protracted COVID-19.•High-titre CCP may be useful for late protracted COVID-19 in seronegative patients. Despite vaccination, patients receiving anti-CD20 monoclonal antibodies (mAbs) for multiple sclerosis (MS) or neuromyelitis optica spectrum disorders (NMOSD) have an increased risk of developing severe or protracted COVID-19. The aim of this study was to describe the effect of COVID-19 convalescent plasma (CCP) in patients with MS or NMOSD exposed to anti-CD20 and infected by SARS-CoV-2. This French national, retrospective cohort study was conducted between November 2020 and June 2023. Patients with MS or NMOSD, under anti-CD20 mAbs, with symptomatic COVID-19 and treated by CCP were screened. Protracted COVID-19 was defined by a duration of symptoms > 21 days. The primary endpoint was the overall survival 30 days after CCP administration. Ninety-two patients from 34 hospitals were included, 84 (91%) with MS and 8 (9%) with NMOSD. Overall, 30-day survival was 97% (IC95%: 91-99). SARS-CoV-2 viremia was positive in 47/75 (61%) patients before CCP versus 9/59 (15%) seven days post-CCP. In the 52 patients (57%) with protracted COVID-19, the duration of symptoms before CCP was 51 [28-69] days, including fever in 75% of cases, which disappeared in 100% of patients seven days post-CCP. CCP could be a therapeutic option in patients exposed to anti-CD20 mAbs for inflammatory demyelinating disease, particularly in those with protracted COVID-19.