One thing that isn't obvious to me is exactly how `n` is defined, and how that relates to how many people of that `n` were infected by covid during the trial. E

One thing that isn't obvious to me is exactly how `n` is defined, and how that relates to how many people of that `n` were infected by covid during the trial. E.g. maybe n=2,741 people were vaccinated following the first dosing protocol, but perhaps only a small fraction were infected with covid. So the actual sample sizes being used to estimate the efficacy of each dosing protocol may be smaller.