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

ABSTRACT

BackgroundAmid the coronavirus disease 2019 (COVID-19) crisis, two messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have benefited most people worldwide. While healthy people can acquire sufficient humoral immunity against COVID-19 even in the elderly by vaccination with three doses of vaccine., recent studies have shown that complex factors other than age, including the type of vaccines and immunosuppressive drugs, are associated with immunogenicity in patients with rheumatic musculoskeletal disease (RMD). Identifying factors that contribute to the vulnerability of those patients to acquire not only humoral but also cellular immunity to SARS-CoV-2 despite multiple vaccinations is crucial for establishing an appropriate booster vaccine strategy.ObjectivesTo assess humoral,and T cell immune responses after third doses of mRNA vaccines against SARS-CoV-2.MethodsThis prospective observational study included consecutive RMD patients treated with immunosuppressant who received three doses of mRNA vaccines including BNT162b2 and mRNA-1273. Blood samples were obtained 2-6 weeks after second and third dose of mRNA vaccines. We measured neutralizing antibody titres, which against the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 and seroconversion rates to evaluate the humoral responses. We also assessed T-cell immunity responses using interferon releasing assay against SARS-CoV-2.ResultsA total of 586 patients with RMD treated with mmunosuppressive treatments were enrolled. The mean age was 54 years, and 70% of the patients were female. Seroconversion rates and neutralizing antibody titres after third vaccination of SARS-CoV-2 were significantly higher compared to those after second vaccination (seroconversion rate, 94.5% vs 83.6%, p<0.001;titres of neutralizing antibody, 48.2 IU/mL vs 11.0 IU/mL, p<0.001, respectively). Interferon releasing assay after third vaccinations demonstrated that T cell reaction against SARS-CoV-2 was also increased from that of second vaccination (interferon for antigen 1, 1.11.9 vs 0.61.9, p=0.004,interferon for antigen 2, 1.72.6 vs 0.82.3, p=0.004). Humoral and cellular immunogenicity did not differ between the types of third vaccination including full dose of BNT162 and half dose of mRNA1273.(neutralizing antibody titers, 47.8±76.1 IU/mL vs 49.0±60.1 IU/mL, p<0.001;interferon for antigen 1, 1.12.0 vs 1.01.5, p=0.004, respectively). Attenuated humoral response to third vaccination was associated with BNT162b2 as second vaccination age (>60 years old), glucocorticoid (equivalent to prednisolone > 7.5 mg/day), and immunosuppressant use including mycophenolate, and rituximab. On another front, use of mycophenolate and abatacept or tacrolimus but not rituximab were identified as negative factors for T-cell reactions against SARS-CoV-2. Although 53 patients (9.0%) who had been immunised with third-vaccination contracted COVID-19 during Omicron pandemic phase, no one developed severe pulmonary disease that required corticosteroid therapy.ConclusionOur results demonstrated third mRNA vaccination booster of SARS-CoV-2 contributed to restore both humeral and cellular immunity in RMD patients with immunosuppressants. We also identified that certain immunosuppressive therapy with older RMD patients having BNT162b2 as a second vaccination may need additional booster vaccination.Reference[1]Furer V, Eviatar T, Freund T, et al. Ann Rheum Dis. 2022 Nov;81(11)1594-1602. doi 10.1136/ard-2022-222550.AcknowledgementsNIL.Disclosure of InterestsNone Declared.