Comment on the paper Negative anti-SARS-CoV-2 S antibody response following Pfizer SARS-CoV-2 vaccination in a patient on ocrelizumab: the likely explanation for this phenomenon based on our observations.

Furthermore, it has been reported that MS patients using anti-CD20 therapy have suppressed antibody response to infection with the novel coronavirus (SARS-CoV-2) and to some vaccines (not against COVID-19) [[1], [3]-[5]]. Dear Sirs, We read with great interest the paper by Khayat Khoei et al. which presented negative anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) antibody response after Pfizer SARS-CoV-2 vaccination in a patient with relapsing-remitting multiple sclerosis (RRMS) on ocrelizumab [[1]]. [Extracted from the article]