The Pfizer vax is 95% effective if you go by the Relative Risk Reduction (RRR) calculation, which is what is highlighted. But if you go by the Absolute Risk Reduction (ARR) it's only 0.84% effective.
The first considers only infected individuals in the test and control groups, while the second considers the entire population of both groups. Here's a chart.
The Pfizer vax is 95% effective if you go by the Relative Risk Reduction (RRR) calculation, which is what is highlighted. But if you go by the Absolute Risk Reduction (ARR) it's only 0.84% effective.
The first considers only infected individuals in the test and control groups, while the second considers the entire population of both groups. Here's a chart.