Thread by @NavroopSingh_

First-dose ChAdOx1 (COVIDSHIELD) and BNT162b2 (Pfizer) COVID-19 vaccines and thrombocytopenic, thromboembolic and hemorrhagic events in Scotland

nature.com/articles/s4159…

first dose of ChAdOx1 was found to be associated with small increased risks of ITP, with suggestive evidence of an increased risk of arterial thromboembolic and hemorrhagic events.

The attenuation of effect found in the SCCS analysis means that there is the potential for overestimation of the reported results, which might indicate the presence of some residual confounding or confounding by indication.

Public health authorities should inform their jurisdictions of these relatively small increased risks associated with ChAdOx1 (COVIDSHIELD). No positive associations were seen between BNT162b2 (Pfizer) and thrombocytopenic, thromboembolic and hemorrhagic events.

To our knowledge, this is the one of the first real-world contemporaneous studies identifying all vaccinated individuals within a national population and assessing COVID-19 vaccine-related thrombocytopenic, venous or arterial thromboembolic and hemorrhagic adverse events.