Covid-19: How will the new Pfizer covid vaccine work?
The Pfizer/BioNTech coronavirus vaccine is the first one in the UK to be approved for mass use, with people receiving injections within a week.
England's Deputy Chief Medical Officer says the first wave of vaccinations could prevent up to 99% of Covid-19 hospital admissions and deaths.
But rolling it out isn't straightforward because of the unique way it needs to be stored.
BBC health correspondent Laura Foster explains some of the logistics around it.
Video by Laura Foster, Terry Saunders and Mel Lou.
