It’s possible that there is one contaminated batch, but that does not say much for the quality control systems either of AZ or the regulators, who run checks on all batches. Admittedly all are working under extreme pressure to keep volume up. However, even if there is a problem with a batch or two, the incidence of clotting is still so low as to be within ‘normal’ expectations regardless of vaccination.
Dunno Col. excessive caution more likely. Delaying jabs doesn’t help anyone. Like Blymie above I do recall now being asked if I was on a any blood thinning medication when I got my jab, so perhaps there is a perceived risk here too. But the numbers of incidents available to the public at least are tiny. It would be chronically daft, not to mention illegal, for either AZ or the regulator to suppress safety information.
Also just noticed that vaccination passports, of a type, already exist. I have the NHS app on my phone (not the test and trace app) because it makes repeat prescriptions very quick and easy. I noticed today that in my health record/medicines section the dose of vaccine I had on 3 March is recorded in some detail. Presumably this is a more dependable ‘proof’ of vaccination than the little card they give you with the batch number on when you get the jab. Quite impressed that everything is joined up enough to get on my central record, especially as I didn’t book the jab via my GP.