FWIW, N=94 seems ridiculously small to me. I realize there's ethical concerns in increasing exposure etc but in my experience, that's in the ballpark of sample sizes where unacknowledged heterogeneity can be manipulated to distort findings.

I'm not suggesting Pfizer is up to something nefarious, just that the biomedical literature is littered with studies with N < 100 for the outcomes of interest and they don't replicate. The N > 40k in some ways is irrelevant if none of those participants have the processes in play. It's more like recruiting N >40k to get N=94 to study.

I'm also not suggesting with 90% effectiveness that there's probably no effect, just that my guess is a true value of 60% isn't outside the realm of possibility once you consider all the factors that could be in play besides the random sampling variation that's assumed by their tests.