There are two questions
(1) If one continues to take ocrelizumab, will the T cell immunity following COVID-19 vaccination be enough to stop severe COVID-19.
(2) Is it safe to miss a dose to allow B cells to repopulate to allow a B cell-vaccine response.
We dont have a definative answer yet for number 1, but we know that it will not necessarily stop you getting symptomatic COVID-19, and severe COVID can occur in double Vaccinated, I am sure there is some protection, however more and more data addresses number 2. This is a study from UK where there missed a dose of ocrelizumab
Clinical impact of Ocrelizumab extended interval dosing during the COVID-19 pandemic and associations with CD19+B-cell repopulation.Sahi NK, Abidi SMA, Salim O, Abraham R, Kalra S, Al-Araji A.Mult Scler Relat Disord. 2021 Sep 27;56:103287.
In this retrospective clinical audit, 136 patients with MS received Ocrelizumab during the COVID-19 pandemic. There was no significant difference in clinical relapse rate or radiological activity between 67 patients who received extended interval dosing (EID) (≥30 weeks, mean 48.3 ± 5.9 weeks) compared to standard interval dosing (<30 weeks) with average follow-up of over 4 months. CD19+ B-cell repopulation occurred in 94% (p<0.001) of EID patients at re-infusion and correlated strongly with re-dosing interval (rs=0.738, p=<0.0001) but was not associated with inflammatory disease activity. EID did not impact short-term disease activity, despite significant CD19+ B-cell repopulation and warrants long-term prospective study.