clots and the astrazeneca vaccine, there have been questions about what it means for the uk's vaccine programme and people's confidence in it. our health editor hugh pym explains the potential problems and the effect they've had. lockdown is easing, the vaccination programme is going well. but today there has been a change of course, raising new questions. first, what is the risk with oxford—astrazeneca? it is lower the older you are, as the potential for serious illness with covid is weighed against possible harms from blood clots. some medication, including the contraceptive pill, also has a very small blood clot risk. anyone who has had a firstjab and four days or more after that gets severe headaches, blurred vision or certain other symptoms should contact a medical professional. a committee of europe's regulator, known as prac, drew this conclusion. we know the benefits of the astrazeneca vaccine have been established. it prevents covid disease,