Good questions!

In response to a previous question on this article, Tensor has posted the algorithm for reproducing the numbers in IA2. I have implemented Tensor’s algorithm in the Python code that accompanies this article. Try going through that code and let me know if you have any questions about it.

About your second question, the minimum trial size is calculated as follows:

L=(1+the loss to follow-up factor). In this case 1+20%

IR_control = the incidence rate in the control group which Pfizer has assumed to be 1.3% per year or 0.65% per 6 months.