Consider the following data abstracted from the safety and efficacy study of the Pfizer vaccine (BNT162b2) (Polack FP et. al. N Engl J Med 2020;383:2603-15). The investigators reported that 17,411 subjects received the vaccine, while 17,511 received the placebo. 8 of those vaccinated and 162 of those given a placebo developed the disease.

A. Set a 2 by 2 table. [2 points].

B. Calculate the risk or chance of getting the disease among the vaccinated group [2 points]. (b) What proportion of the vaccinated people were disease-free for at least 3 months? [2 points].

C. Calculate the appropriate measure of association between vaccine exposure and COVID-19, and provide an explanation of your findings [2 points]. (b) Calculate the corresponding 95% CI and comment on the meaning [3 points].