Inactivated SARS-CoV-2 vaccine does not influence the profile of prothrombotic antibody nor increase the risk of thrombosis in a prospective Chinese cohort

The presence of antiphospholipid antibodies was shown to be associated with thrombosis in coronavirus disease 2019 (COVID-19) patients. Recently, according to reports from several studies, the vaccine induced immune thrombotic thrombocytopenia is mediated by anti-platelet factor 4 (PF4)-polyanion complex in adenovirus-vectored COVID-19 vaccine recipients. It is impendent to explore whether inactivated COVID-19 vaccine widely used in China influences prothrombotic autoantibody production and induces thrombosis. In this prospective study, we recruited 406 healthcare workers who received two doses, 21 days apart, of inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (BBIBP-CorV, Sinopharm). Paired blood samples taken before vaccination and four weeks after the second vaccination were used in detecting prothrombotic autoantibodies, including anticardiolipin (aCL), anti -B2 glycoprotein I (aB2GP1), anti-phosphatidylserine/prothrombin (aPS/PT), and anti-PF4heparin. The seroconversion rate of SARS-CoV-2 specific antibodies was 95.81% (389/406) four weeks after vaccination. None of the subjects had spontaneous thrombosis or thrombocytopenia over a minimum follow-up period of eight weeks. There was no significant difference in the presence of all ten autoantibodies between samples collected before and after vaccination: for aCL, IgG (7 vs. 8, P = 0.76), IgM (41 vs. 44, P = 0.73), IgA (4 vs. 4, P = 1.00); anti-B2GP1, IgG (7 vs. 6, P = 0.78), IgM (6 vs. 5, P = 0.76), IgA (3 vs. 5, P = 0.72); aPS/PT IgG (0 vs. 0, P = 1.00), IgM (6 vs. 5, P = 0.76); aPF4-heparin (2 vs. 7, P = 0.18), and antinuclear antibody (ANA) (18 vs. 21, P = 0.62). Notably, seven cases presented with anti-PF4-heparin antibodies (range: 1.18-1.79 U/mL) after vaccination, and none of them exhibited any sign of thrombotic disorder. In conclusion, inactivated SARS-CoV-2 vaccine does not influence the profile of antiphospholipid antibody and anti-PF4-heparin antibody nor increase the risk of thrombosis. (c) 2021 Science China Press. Published by Elsevier B.V. and Science China Press. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Research conducted in China indicates that after receiving an inactivated COVID-19 vaccine, there were no significant changes in prothrombotic autoantibody levels or increased risk of thrombosis observed.