The Pfizer vaccine trial has 43,000 participants. Exact breakdown between treatment and placebo groups is not given, but they do provide the number of covid cases in each group. Currently, there are 162 covid cases in the placebo group.

Assuming a 50/50 split, 99.25% of the placebo group did not get covid.

Additionally, only 9 in the placebo group had a "severe case" and no one died. That is 99.96% in the placebo group did not have a severe case.

Caveats

We need to know the overall...