A number of studies have documented a similar lack of increased antibody titers against CL, β2GP1, PF4-heparin and phosphatidylserine/prothrombin (aPS/PT) following use of the Sinovac–CoronaVac inactivated whole-SARS-CoV-2-virus vaccine [72,244,248], with only seven cases developing low-titer anti-PF4-heparin antibodies (range: 1.18–1.79 U/mL) after vaccination, and none of these exhibiting any sign of thrombotic disorder [72]. Here, PF4 is linked to thrombotic disease.