A healthcare worker prepares a syringe with the Pfizer-BioNTech Covid-19 vaccine at a pop-up COVID-19 vaccination clinic at the Montague Charter Academy of Arts and Sciences in Arleta, California, USA, 23 August 2021. The Food and Drug Administration on Monday granted full approval to Pfizer and BioNTech's Covid-19 vaccine, making it the first FDA approved Covid-19 vaccine in the nation.  ANSA/CAROLINE BREHMAN