2/ My reading of the Pfizer results is that protection emerges after about 10 days (which is about where one would expect people to be come seropositive) and flattens after that, even before the 28-day mark where the second dose would be expected to confer added benefit.

3/ The problem is it's absolutely urgent to shrink the susceptible population (it would be ideal if people would tighten containment behaviors too). At minimum, may be wise to give all available doses, and let later supply provide second dose rather than holding in the interim.

4/ The arithmetic here is that 1 infection will result in expected fatalities equal to:

fj + fc*Rt = infection fatality rate of person j + fatality rate of j's contacts x expected infections resulting from j

Priority: Elderly/high risks, and those in networks that contact them