Very small blood clot risk after first AstraZeneca COVID shot – UK studies

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(Reuters) – A large study into rare blood clots linked with AstraZeneca’s (AZN.L) COVID-19 vaccine found between just one and three cases per million, and only after the first dose, shedding fresh light on the side-effects from the shot.

Researchers have sought to analyse any link between COVID-19 vaccines and rare blood clots in the brain, arteries or veins – sometimes accompanied by low platelets, reports of which led many nations last year to pause use of the AstraZeneca shot, which was developed with Oxford University.

A study published in the PLOS Medicine journal on Tuesday looked at health records of 46 million adults in England between December 2020 and March 2021 to assess the risk of clots in the month after vaccination with either the Pfizer-BioNTech vaccine or AstraZeneca-Oxford shot, compared with the unvaccinated.

It was carried out by William Whiteley of the University of Edinburgh and Britain’s BHF Data Science Centre.

It found no risk of major arterial and venous thrombotic events in those aged 70 or over with either of the vaccines.

And while the risk of intracranial venous thrombosis (ICVT) following the AstraZeneca-Oxford vaccine was nearly double in those under 70, that was equal to between just one and three cases per million.

The risks of ICVT and hospitalisation with thrombocytopenia “are likely to be outweighed by the vaccines’ effect in reducing COVID-19 mortality and morbidity,” the study’s authors said.

 

Reuters source:

https://www.reuters.com/business/healthcare-pharmaceuticals/very-small-blood-clot-risk-after-first-astrazeneca-covid-shot-uk-studies-2022-02-22