Lupus anticoagulant activity and thrombosis post COVID-19 vaccination.

Some reports have discussed the development of a new entity called vaccine-induced immune thrombotic thrombocytopenia after COVID-19 vaccination. In this case series, we are describing four patients who have developed lupus anticoagulant-associated venous thromboembolism after Pfizer mRNA COVID-19 vaccination. All were COVID-19 negative on admission. Three had developed thrombosis after the first dose and one after the second dose of vaccination. All of them had venous thrombosis. Three patients developed thrombosis 2 weeks after vaccination and the fourth patient had developed thrombosis after 3 weeks of vaccination. None of the patients had thrombocytopenia on or during admission as seen in the case of vaccine-induced immune thrombotic thrombocytopenia. All patients had positive lupus anticoagulant and negative anticardiolipin antibodies and antibeta2 glycoprotein I. All of them were stable on discharge and were treated with low molecular weight heparin followed by warfarin. We suggest the presence of a possible link between the development of antiphospholipid antibodies and COVID-19 vaccine that requires further assessment.