Thrombosis and Thrombocytopenia after ChAdOx1 nCoV-19 Vaccination
Nina Haagenrud Schultz, Ingvild Hausberg Sørvoll, Annika E. Michelsen, Ludvig A. Munthe, Fridtjof Lund‐Johansen, Maria Therese Ahlén, Markus Wiedmann, Anne Hege Aamodt, Thor Håkon Skattør, Geir E. Tjønnfjord, Pål André Holme
Abstract
We report findings in five patients who presented with venous thrombosis and thrombocytopenia 7 to 10 days after receiving the first dose of the ChAdOx1 nCoV-19 adenoviral vector vaccine against coronavirus disease 2019 (Covid-19). The patients were health care workers who were 32 to 54 years of age. All the patients had high levels of antibodies to platelet factor 4-polyanion complexes; however, they had had no previous exposure to heparin. Because the five cases occurred in a population of more than 130,000 vaccinated persons, we propose that they represent a rare vaccine-related variant of spontaneous heparin-induced thrombocytopenia that we refer to as vaccine-induced immune thrombotic thrombocytopenia.