Effects of casirivimab/imdevimab on systemic and mucosal immunity against SARS-CoV-2 in B-cell depleted patients with autoimmune rheumatic diseases refractory to vaccination

The latter has become of particular concern, as treatment with anti-CD20 antibody rituximab is associated with more severe courses of COVID-191 and abolished or severely impaired humoral responses to SARS-CoV-2 vaccination.2 While newly initiated B-cell depletion is usually preceded by SARS-CoV-2 vaccination, several situations leave patients without protective immunity during treatment. [...]B-cell depletion is often long-lasting and needs to be repeated to prevent potentially life-threatening flares. [...]strategies need to be developed providing anti-SARS-CoV-2 immunity in such patients. Furthermore, substantial levels of casirivimab/imdevimab were found in saliva, exceeding the levels of anti-SARS-CoV-2-specific IgG observed in healthy controls after infection or vaccination4. [...]mAbs also seem to offer mucosal protection from SARS-CoV-2, comparable to active immunisation.