Journal of Thrombosis and Haemostasis | 2021
An observational study to identify the prevalence of thrombocytopenia and anti‐PF4/polyanion antibodies in Norwegian health care workers after COVID‐19 vaccination
Abstract
The COVID‐19 vaccine from AstraZeneca (AZD1222) is one of several vaccines introduced to provide immunity against SARS‐CoV‐2. Recently, more than 50 cases have been reported presenting a combination of thrombosis, thrombocytopenia, and remarkably high levels of anti‐platelet factor 4 (PF4)/polyanion antibodies post‐AZD1222 vaccination. Now linked to the vaccine, the condition is referred to as vaccine‐induced immune thrombotic thrombocytopenia. The European Medicines Agency still recommends vaccination with AZD1222, but several European countries have temporally paused and/or restricted its use because of the perceived risk of this severe side effect. Because there is no description of PF4/polyanion antibody testing in the clinical trials, knowledge about the prevalence of such antibodies in a vaccinated cohort is needed.