Humoral Immune Response To Sars-Cov-2 Third Vaccine In Patients With Autoimmune Rheumatic Diseases Without Seroconversion After The Initial 2-Dose Regimen

CORBALAN, P; PERA, M; ESPASA, G; LEGUIZAMON, ML; BARBAGLIA, A; BERTOLACCINI, M; GONZALEZ LUCERO, L; SUELDO, H; CHEHÍN, R; TOMAS GRAU, RH; PLOPER, D; VERA PINGITORE, E; SOCIAS, B; AVILA, CÉSAR L.; CAZORLA, SILVIA I; MALDONADO GALDEANO, C; BELLOMIO, V

Rio de Janeiro

Congreso; 25 Pan-American Congress of Rheumatology; 2023

Objectives: To evaluate the humoral immune response to the third dose (booster) of vaccine against SARS-CoV-2 in patients with autoimmune rheumatic diseases who were seronegative after a two-dose regimen.Methods: Observational study. Patients with autoimmune rheumatic diseases who had no seroconversion after a two- dose vaccine schedule against SARS-CoV-2 were included. To assess the humoral immune response, anti-RBD IgG (S protein receptor binding domain) neutralizing antibody titers were determined by ELISA (cutoff titer 200). The determination was made between 30 to 45 days after the third dose.Results: From 66 patients who received SARS-CoV-2 vaccination, 18 patients (29.5%) were seronegative after a two- dose schedule. 61% with SLE, 77% with comorbidities (61% with arterial hypertension, p 0.03). Patients were on treatment: 10 with prednisone (8 with doses greater than 10 mg/dl, p 0.01), 10 with Hydroxychloroquine, 1 with Methotrexate, 1 with Leflunomide, 4 with Azathioprine, 5 with Mycophenolate Mofetil and 5 with Rituximab (they are the total number of non-responders on biological treatment, p 0.03). Regarding the primary vaccination regimen, 11 received BBIBP-CorV (p 0.01), 5 AZD1222, 1 Gam-COVID-Vac and 1 mRNA1273/Gam-COVID-Vac heterologous scheme. Of these 18 non-responders, 14 received a third dose; 9 patients (62%) presented anti-RBD IgG detectable. Of the 5 patients who did not respond to booster vaccination, 3 had received BBIBP-CorV as the initial schedule and the vaccines applied as a third dose were Ad5-nCoV (1), BNT162b2 (1), AZD 1222 (2) and Gam- COVID-Vac (1) . They were being treated with: Rituximab (2), Azathioprine (2) and Mycophenolate Mofetil (1). Treatment with higher doses of prednisone was the only factor associated with non-seroconversion to the third dose (8 ± 4.5; p 0.02).Conclusion: The third dose of SARS-CoV-2 vaccine allowed to improve the serological response to vaccination, achieving a seroconversion of 62% in this group of patients.