A large study into rare blood clots linked with AstraZeneca's 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 the use of the AstraZeneca shot, which was developed with Oxford University.

A study published in the Plos Medicine journal yesterday looked at health records of 46 million adults in...