Antibody response to SARS-CoV-2 vaccination following typical and three-dose dosing schedules in multiple sclerosis patients treated with disease modifying therapies

Background: Immunizations against SARS-CoV-2 virus are now available and recommended, but the effect of additional dosing of the vaccine in immunocompromised MS patients is unknown. Methods: Part I -A retrospective chart review of MS patients who were vaccinated against SARS-CoV-2 and tested commercially for Sars Covid Spike Protein Antibody between March 1 - June 30, 2021. Part II -Patients on treatment with anti-CD20 infusion medications who received a SARS-CoV-2 third mRNA vaccination dose August 13, 2021 - October 31, 2021 and were subsequently commercially tested for Sars Covid Spike Protein Antibody. Results: Part I -A total of N = 208 MS patients, age range 23-76 were tested, with 49% (102/208) demonstrating a humoral response. Stratified by DMT type, patients treated with interferon, teriflunomide, or a remote history of alemtuzumab (> 2 years since last DMT) yielded 100% measurable antibodies; > 90% amongst patients treated with natalizumab, fumarates and glatiramer acetate; < 50% measurable antibodies following vaccination in S1P modulators and anti-CD20 treated patients. Subsequently, in Part II - N = 40 patients on anti-CD20 treatments (33 ocrelizumab, 7 rituximab) who received 3 mRNA vaccinations yielded 20% humoral response. Conclusions: MS patients are able to mount a humoral vaccine response to SARS-CoV-2, irrespective of the vaccine type administered; patients treated with S1P modulators and anti-CD20 agents are least likely to mount such a response with a typical dosing schedule. Patients treated with ocrelizumab/rituximab show a similar modest humoral immune system benefit following three doses as with standard dosing.