COVID-19 Vaccination in Multiple Sclerosis and Inflammatory Diseases: Effects from Disease-Modifying Therapy, Long-Term Seroprevalence and Breakthrough Infections

Background: To determine the effect of disease-modifying therapies (DMT) on humoral postvaccine seroconversion, long-term humoral response, and breakthrough COVID-19 infections in persons with multiple sclerosis (PwMS) and other neuroinflammatory disorders. Methods: A total of 757 PwMS and other neuroinflammatory disorders were recruited in two MS centers and vaccinated with one of the FDA-approved vaccines (BNT162b2, mRNA-1273, Ad26.COV2.S). The primary outcomes are the rate of humoral postvaccine seroconversion and anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) immunoglobulin G (IgG) differences between patients on different DMTs. Secondary measures include breakthrough infections and humoral response after six months. Other outcomes include differences in vaccine response between SARS-CoV-2 vaccines and the effects of age and comorbidities on the vaccine response. Results: A total of 465 (68.4%) PwMS and 55 (74.3%) patients with neuroinflammatory diseases were seropositive at 4–12 weeks after vaccination. A significant difference in seroconversion based on the DMT used at the time of vaccination (p < 0.001) was observed, with the lowest rates seen in patients treated with anti-CD20 antibodies (23.2%) and sphingosine-1-phosphate modulators (S1P) (30.8%). In seropositive patients, there was a significant decrease in anti-SARS IgG from mean 20.0 to 4.7 at six months (p = 0.004). Thirty-nine patients had breakthrough infection, but only two seronegative patients required hospitalization. mRNA vaccines resulted in significantly greater seroconversion compared to Ad26.COV2.S (p < 0.001). Older age and presence of cardiovascular comorbidities were associated with lower anti-SARS IgG (p = 0.021 and p = 0.003, respectively) Conclusions: PwMS and neuroinflammatory disorders treated with anti-CD20 and S1P medications have lower humoral response after anti-SARS-CoV-2 vaccination, even after booster dose. Waning of the humoral response puts vaccinated PwMS at a greater risk of COVID-19 breakthrough.