[patrickgzill]

Do remember that the current flu vaccine (as an example) has an efficacy rate of less than 65%. So even if 100% of the population were vaccinated, herd immunity would not be possible.

Herd immunity requires about 75% + efficacy of the vaccines (and assuming 100% of the target population is vaccinated), from what I can understand (it varies based on how the disease being vaccinated against, is spread).

There are vaccines being sold and marketed, that have efficacy rates as low as 35%.

[patmcguire]

Is efficacy binary? A partially protected person could spread less and recover more quickly than someone who isn't protected. I'm not sure enough of the math to know whether 100% of people being 65% protected works the same as 65% of the people being 100% protected, but it might not be.

[tedunangst]

Mostly binary. The flu vaccine protects ~99% against some strains and 0% against others.

[fnordfnordfnord]

It may not be, but I think that is the way it is modeled.