The risk of thrombosis at 11 excess events per 100 000 vaccinations are higher than estimated by the European Medicines Agency. The EMA estimates the risk of thrombosis to be between 1 and 2 per 100 000 people, depending on age. Among the venous thromboembolic events, the most notable was cerebral venous thrombosis, which was about 20 times more common after the Oxford-AstraZeneca vaccine than expected with an excess risk of 2.5 per 100 000 vaccinations. Venous thromboembolic events were more common in women than in men and were also more common in people aged 18-44 than in those aged 45-65. Thrombocytopenia and bleeding were mildly increased after vaccination, but not significantly.
Study Paper here: Arterial events, venous thromboembolism, thrombocytopenia, and bleeding after vaccination with Oxford-AstraZeneca ChAdOx1-S in Denmark and Norway: population based cohort study