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

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