Background/Purpose: Several trials have reported lower seroconversion rates in patients with autoimmune rheumatic diseases than in healthy patients. In Argentina, the vaccines against SARS-CoV-2 that were available during the development of this study were: Sputnik V (Gam-COVID-Vac), AstraZeneca (ChAdOx1 nCov-19), Sinopharm (BBIBP-CorV) and Moderna (mRNA-1273). Limited information is available about vaccines against SARS-CoV-2 with inactivated virus or viral vector in autoimmune patients.

The purpose of this study was to evaluate humoral immune response to vaccines against SARS-CoV-2 in patients with autoimmune rheumatic diseases; to compare humoral response among patients with Systemic Lupus Erythematosus (SLE) and other autoimmune diseases and to analyse associated variables.

Methods: We included patients with autoimmune rheumatic diseases vaccinated against SARS-CoV-2 from June to November 2021. To evaluate the humoral immune response, neutralizing anti-S-RBD (receptor binding domain) IgG antibody titres were determined by ELISA “In House” test with a cut-off titre of 200 (IMMCA). Serological determinations were defined at: T0 or baseline: 1st vaccine dose, T1: 14 ± 2 days after 1st dose, T2: 2nd dose, T3: 21- 45 days after 2nd dose, T4: 30 days after 3rd dose, T5: 6 months and T6: 12 months after 3rd dose.

Results: We made a preliminary analysis at T3. Sixty six patients were included, 91% women with a mean age of 40.7 ± 11.4 years; 53% with SLE, 15.2% Rheumatoid Arthritis, 7.6% Systemic Sclerosis, 7.6% Juvenile Idiopathic Arthritis, 7.6% Systemic Vasculitis and 9% other diagnoses. Sixteen patients (24.2%) had previous COVID19 (75% mild symptoms). Treatments at baseline: corticosteroids 37.9% with prednisone mean dose 4.12 ± 8 mg/day, cDMARDs 75.7% and bDMARDs 18.2%. The vaccines applied were: AstraZeneca 38.3%, Sinopharm 31.7%, Sputnik V 19%, and combined schedule Sputnik V/ Moderna in 11%. At baseline, 28.8% had detectable anti-S-RBD IgG antibodies. This frequency increased to 48.4% at 1st dose and 70.2% at 2nd dose. Vaccination with Sinopharm and treatment with bDMARD were associated with lower seroconversion rates and lower antibody titre (p 0.028, p 0.02, respectively). None of the 5 patients with Rituximab showed seroconversion. Levels of anti-S-RBD IgG antibodies were similar between patients with SLE and the other rheumatic diseases (p=NS). Vaccine applied at the 1st dose and hypertension disease were independently associated with seroconversion in the regression analysis. The chance of responding to vaccination was 13 and 9 times higher for those who received Sputnik V (OR 12.78; 95% CI 1.46- 315.9) or AstraZeneca (OR 8.61; 95% CI 1.63 – 72.5) respectively, than Sinopharm in the 1st dose. The chance of being a responder was 88% lower for hypertensive patients (OR 0.12; 95% CI 0.02-0.58).

Conclusion: Two-dose vaccination for SARS-CoV-2 in patients with autoimmune rheumatic diseases presented a seroconversion rate of 70.2%. There were no differences in the serological response between patients with SLE and other rheumatic diseases. Seroconversion and antibody titres levels were associated with the type of vaccine applied, being Sinopharm who presented the lowest response.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/vaccination-immune-response-against-sars-cov-2-in-patients-with-autoimmune-rheumatic-diseases/