AB1286 HUMORAL AND CELLULAR IMMUNOGENICITY INDUCED BY THIRD BOOSTER OF SARS-CoV-2 VACCINES IN PATIENTS WITH RHEUMATIC MUSCULOSKELETAL DISEASES

Background Amid the coronavirus disease 2019 (COVID-19) crisis, two messenger RNA (mRNA) vaccines against severe acute respiratory syndrome 2 (SARS-CoV-2) have benefited most people worldwide. While healthy can acquire sufficient humoral immunity COVID-19 even in elderly by vaccination with three doses of vaccine., recent studies shown that complex factors other than age, including type and immunosuppressive drugs, are associated immunogenicity patients rheumatic musculoskeletal (RMD). Identifying contribute to vulnerability those not only but also cellular SARS-CoV-2 despite multiple vaccinations is crucial for establishing an appropriate booster vaccine strategy. Objectives To assess humoral,and T cell immune responses after third mRNA SARS-CoV-2. Methods This prospective observational study included consecutive RMD treated immunosuppressant who received BNT162b2 mRNA-1273. Blood samples were obtained 2-6 weeks second dose vaccines. We measured neutralizing antibody titres, which receptor-binding domain (RBD) spike protein seroconversion rates evaluate responses. assessed T-cell using interferon releasing assay Results A total 586 mmunosuppressive treatments enrolled. The mean age was 54 years, 70% female. Seroconversion titres significantly higher compared (seroconversion rate, 94.5% vs 83.6%, p<0.001; antibody, 48.2 IU/mL 11.0 IU/mL, p<0.001, respectively). Interferon demonstrated reaction increased from (interferon antigen 1, 1.11.9 0.61.9, p=0.004,interferon 2, 1.72.6 0.82.3, p=0.004). Humoral did differ between types full BNT162 half mRNA1273.(neutralizing titers, 47.8±76.1 49.0±60.1 1.12.0 1.01.5, p=0.004, Attenuated response as (>60 years old), glucocorticoid (equivalent prednisolone > 7.5 mg/day), use mycophenolate, rituximab. On another front, mycophenolate abatacept or tacrolimus rituximab identified negative reactions Although 53 (9.0%) had been immunised third-vaccination contracted during Omicron pandemic phase, no one developed pulmonary required corticosteroid therapy. Conclusion Our results contributed restore both humeral immunosuppressants. certain therapy older having a may need additional vaccination. Reference [1]Furer V, Eviatar T, Freund et al. Ann Rheum Dis. 2022 Nov;81(11):1594-1602. doi: 10.1136/ard-2022-222550. Acknowledgements: NIL. Disclosure Interests None Declared.