the Oxford-Astra Zeneca Covid 19 Vaccine Delivered for National Roll Out next week

What is the significance of the Astra Zeneca vaccine in the context of the vaccination program?

How has the guidance regarding the timing of vaccine doses changed recently?

What is the current target for the number of vaccinations per week, and how does it compare to the current progress?

What challenges are faced in the vaccination rollout according to the text?

What are the potential risks associated with delaying the second dose of the Pfizer vaccine?