Consecutive MS patients from NYU MS Care Center were invited to participate if they completed COVID-19 vaccination ≥6 weeks previously. Immune testing included anti-spike RBD antibody (Elecsys Anti-SARS-CoV-2) (Roche Diagnostics); multi-epitope bead-based immunoassays (MBI) of antibody-responses to SARS-COV-2 spike proteins (threshold of ‘positivity’ was chosen as 2 SD below non-OCR mean); T-cell responses to SARS-CoV-2 Spike protein using IFNγ enzyme-linked immune-absorbent spot (Invitrogen) and TruCulture (Myriad RBM) assays; high dimensional immunophenotyping; live virus immunofluorescence-based microneutralization assay.

Antibody and T cell data was available on 145/355 patients enrolled to date (mean age: 40.0 years; 75% female; 48% non-white; 39% on OCR; 12% with prior COVID-19 infection; vaccines: 58% Pfizer/BioNTech, 36% Moderna and 6% Johnson&Johnson; median vaccine-to-sample time: 93 (+/-32) days). In OCR, Elecsys Anti-SARS-CoV-2 Ab titers were detected in 30/63 (48%; mean antibody titer in log scale: 1.63) and in non-OCR - in 78/81 (96%, mean Ab titer in log scale: 2.83; p<0.0001). In OCR, antibody response by MBI were detected in 41/57 (72%, mean level in log scale: 3.09) and in non OCR - in 68/72 (94%, mean level in log scale: 4.08; p<0.001). Neutralizing antibodies were detected in 10/42 (38%) of OCR and 24/43 (56%) of non-OCR (p=0.1). T-cell activation based on induced IFNg secretion (TruCulture) was observed in 50/64 (78%) OCR and 43/81 (53%) non-OCR (p=0.002).

Preliminary results suggest robust vaccine-specific T-cell immune response to SARS-CoV2 vaccines in B-cell depleted patients, but markedly attenuated antibody responses. Final results of pre-planned multivariable analyses stratified by DMT class and high-dimensional immunophenotyping will be presented.