B Cell Reconstitution Is Strongly Associated With COVID-19 Vaccine Responsiveness in Rheumatic Disease Patients Who Received Treatment With Rituximab.

B cell reconstitution and a longer time since a patient's last exposure to RTX are associated with a positive serologic response to the COVID-19 vaccine. Strategies for maximizing vaccine responsiveness in patients who receive treatment with RTX should incorporate assessment of B cell reconstitution.