Thromboembolism and the Oxford–AstraZeneca COVID-19 vaccine: side-effect or coincidence?

Danish registry study (n=4, 915 ,426, 9 years of data) suggests that the reported number of thromboembolic events with the AZ vaccine does not seem to be increased vs incidence rates from the entire Danish population before the introduction of the vaccination programme.

SPS commentary:

Authors highlight that the findings should be interpreted with caution, and in the context of the limitations of the study. The number of cases of thromboembolism reported in relation to the AZ COVID-19 vaccine cannot be directly compared to the numbers estimated based on the incidence rates from the Danish population for several reasons. First, data on the sex and age distribution from those who received the COVID-19 vaccine are not yet publicly available. Second, data on the duration of the period during which the AZ COVID-19 vaccinated population developed the reported thromboembolic events are also not publicly available, making it impossible to estimate incidence rates for this population. Third, detailed clinical descriptions of the thromboembolic events reported in relation to AZ COVID-19 vaccinations are still lacking.

The Lancet