The particular concern with the AstraZeneca vaccine is the rare combination of blood clots with low blood platelet count (thrombosis with thrombocytopenia syndr

The particular concern with the AstraZeneca vaccine is the rare combination of blood clots with low blood platelet count (thrombosis with thrombocytopenia syndrome - TTS), not just blood clots in general. Accordingly the Eurosurveillance modeling study [a] (which the Irish Examiner article you cited [0] is based upon) studied specifically the risks of TTS. Neither of the papers that these links [1 & 2] reference indicate that either of the mRNA vaccines are associated with TTS. The first pre-print [b]: > No safety signals were seen for ATE or TTS. > Rates of thrombosis with concomitant thrombocytopenia after vaccination with BNT162b2 were low and in line with expected rates The second study [c] examined only the risk of cerebral venous thrombosis (CVT) and portal venous thrombosis (PVT) after COVID-19, and did not assess the safety of the vaccines: > Importantly, the present study cannot be used to draw conclusions on the relative risk of developing a CVT or PVT after receiving an mRNA vaccine compared to the baseline incidence or compared to other vaccines. Far larger samples are needed (such as those used by the EMA and the FDA pharmacovigilance studies) because the events have so far been found to be extremely rare. The observed incidence of CVT in the matched cohort of people who received an mRNA vaccine is compatible with even the lowest estimate of the baseline rate in the USA of 0.53 per million people in any 2-week period (binomial test: P=0.18). The marketwatch thing [2] seems pretty misleading IMO as it implies conclusions that the researchers specifically warned cannot be drawn from the study - the relative risk of developing CVT or PVT after receiving one vaccine when compared to another vaccine. [a]: https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2021.26.26.2100533 https://www.eurosurveillance.org/content/10.2807/1560-7917.E... [b]: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3886421 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3886421 [c]: https://osf.io/a9jdq/ https://osf.io/a9jdq/