Thrombotic events following Covid-19 vaccines compared to Influenza vaccines.

Importance: The actual risk of thrombotic events after Covid-19 vaccination is unknown.

Objective: To evaluate the risk of thrombotic events after Covid-19 vaccination.

Design: Retrospective cohort study which included consecutive adult patients vaccinated with the first dose of Covid-19 vaccine between January 1 and May 30, 2021, and a historic control group, defined as consecutive patients vaccinated with influenza vaccine between March 1 and July 30, 2019.