Maintenance of protective immunity to COVID-19 vaccines in multiple sclerosis patients on B cell-depleting therapy

Immune-mediated protection generated to COVID-19 mRNA vaccines is correlated to the presence of anti-Spike protein neutralizing antibodies. B cell depleting (BCD) therapies used to treat multiple sclerosis (MS), diminish this humoral response, though T cell-mediated immunity can be generated. To study the long-term persistence of these differential responses, the effects of different types and modes of immune modulators, and the resultant effects of protection in patients with MS, we evaluated the humoral and cellular response to COVID-19 vaccines in patients with MS from four centers, ranging from one to 70 weeks post-vaccination. BCD therapies in patients with MS significantly reduced the antibody response and enhanced the cellular response to COVID-19 vaccination, with some variations among different anti-CD20 drugs. Despite these alterations persisting for many months following vaccination, the patients retained protective immunity. These results highlight the critical role of T cell-mediated immunity in anti-viral protection independent of humoral immunity.