COVID-19 vaccine affects neither prothrombotic antibody profile nor thrombosis in primary anti-phospholipid syndrome: a prospective study.

Objective: To explore whether inactivated coronavirus disease 2019 vaccine influences the profile of prothrombotic autoantibodies and induces thrombotic events in primary APS patients.

Methods: We enrolled 39 primary APS patients who received two doses of inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (BBIBPCorV, Sinopharm, Beijing, China) voluntarily in this prospective cohort. Prothrombotic autoantibodies were determined before vaccination and 4 weeks after the second dose of vaccination. Thrombotic disorders were evaluated via hospital site visits and assessments.

Results: There was no significant difference in the presence of all 11 autoantibodies detected before and 4 weeks after vaccination: for aCL, IgG (14 vs 16, P = 0.64), IgM (13 vs 19, P = 0.34), IgA (2 vs 3, P = 0.64); anti-β2GP1, IgG (12 vs 12, P = 1.00), IgM (5 vs 8, P = 0.36), IgA (4 vs 3, P = 0.69); anti-PS/PT IgG (13 vs 16, P = 0.48), IgM (17 vs 22, P = 0.26); LAC (22 vs 28, P = 0.16); aPF4-heparin (0 vs 0, P = 1.00) and ANA (23 vs 26, P = 0.48). Notably, the distribution of the aPL profile in the pre- and post-vaccination cohorts was not affected by SARS-CoV-2 vaccination: for patients with a low-risk aPL profile (11 vs 10, P = 0.799) and patients with a high-risk aPL profile (28 vs 29, P = 0.799), respectively. Furthermore, no case exhibited symptoms of the thrombotic disorder during a minimum follow-up period of 12 weeks. There was no adjustment to the ongoing treatment regimens following SARS-CoV-2 vaccination.

Conclusion: Inactivated SARS-CoV-2 vaccine does not influence the profile of anti-phospholipid antibodies and anti-PF4-heparin antibodies nor induces thrombotic events in primary APS patients.