From Twitter, it looks like the rates of clotting-related issues in UK recipients of the AstraZeneca and Pfizer/​BioNTech vaccines are essentially indistinguishable.
An update to this comment: there is now some evidence to suggest the rates of cerebral venous sinus thrombosis are substantially different in UK recipients of the two vaccines. It is a very low rate (30 in 28 million), but there does seem to be a real difference there.
From Twitter, it looks like the rates of clotting-related issues in UK recipients of the AstraZeneca and Pfizer/​BioNTech vaccines are essentially indistinguishable.
An update to this comment: there is now some evidence to suggest the rates of cerebral venous sinus thrombosis are substantially different in UK recipients of the two vaccines. It is a very low rate (30 in 28 million), but there does seem to be a real difference there.