TABLE 1.

Terms used to describe post COVID‐19 vaccine associated thrombosis with thrombocytopenia

Abbreviation	Stands for	Comments
VIPIT	Vaccine‐induced prothrombotic immune thrombocytopenia	Original term reported by German researchers.17
VITT	Vaccine‐induced immune thrombotic thrombocytopenia or vaccine‐induced immune thrombosis with thrombocytopenia	Term used in subsequent report by the German group,18 as well as separate case series by Norwegian19 and UK20 based groups publishing in the same journal. Perhaps reflecting a variation of the abbreviation HITT, representing the condition of ‘heparin‐induced thrombocytopenia with thrombosis’.
VATT	Vaccine‐associated (immune) thrombotic thrombocytopenia (or thrombosis with thrombocytopenia)	A term supported by other researchers concerned with the terminology ‘induced’ where a clear pathological link to the vaccine is not clear. A broader term excluding ‘immune’ potentially captures other thrombotic events associated with thrombocytopenia and vaccine use, but where an immune relationship is unclear.
TTS	Thrombosis with thrombocytopenia syndrome	A term favoured by some reporting agencies which does not specifically indicate any “vaccine” association. Term not typically utilised by researchers for the condition associated with COVID‐19 vaccine use, since essentially can encompass any condition where thrombosis can be associated with thrombocytopenia, including HITT and thrombotic thrombocytopenia purpura (TTP).