Effect of disease-modifying treatments on antibody-mediated response to anti-COVID19 vaccination in people with multiple sclerosis.

Background: Few data are available so far on the antibody-mediated immune response to anti-SARS-Cov2 vaccination in people with multiple sclerosis (pwMS) treated with disease-modifying treatments (DMTs), therefore this issue was explored in a real-life cohort of pwMS.

Materials And Methods: Retrospective monocentric study on anti-spike protein antibody response in pwMS who had received vaccination for Sars-Cov2. Adverse events following vaccination were also recorded.

Results: One hundred and twenty pwMS were included: 83 females (69%); median age at vaccination 42 years (range 21-73); 112/120 patients (93%) were receiving DMTs at vaccination. Anti-spike protein IgG antibodies were detectable in 102/120 (85%) cases overall, being the proportion lower in pwMS receiving anti-CD20 antibodies (14/31, 45%) compared to non-depletive treatments (77/78, 99%), p < 0.0001. Median anti-spike titre was lower in anti-CD20 antibodies and fingolimod-treated pwMS compared to those receiving other DMTs, and it correlated with anti-CD20 treatment duration (R - 0.93, p < 0.0001) and with age at vaccination in pwMS not receiving depletive treatments (R - 0.25, p = 0.028). Baseline CD19+ cell count (where available) was higher in the responder group than in non-responders, p < 0.0001. Two symptomatic COVID-19 infections were diagnosed over a median follow-up of 5 months (range 2-7); adverse events were aligned with the published literature.

Conclusion: Antibody response to anti-COVID-19 vaccines was detected in most of the pwMS analysed, but frequency of responders was reduced in those receiving CD20 depleting therapies compared to other DMTs-treated pwMS. Investigations on cell-mediated immune response are needed to assess whether a protective immune response is elicited also in non-antibody responders.