Effect sizes and vaccination

This is Joseph

Okay, I want to address a question about effect sizes and vaccination:

I think that this perspective can only be seen as useful in the context of major infectious diseases being eliminated. 

First, many major diseases create long term disability. A good example is blindness -- I am not sure how large the immune benefit would have to be to make blindness a good trade off but it would have to be immense. Same with death -- smallpox killed a lot of its victims. Look at the 20th Maine (in the 1800's) -- during the civil war this regiment (which saw heated combat) still lost almost identical numbers to disease as to action. This was in a period in which the soldiers were definitely being exposed to diseases on campaign and thus challenging their immune systems. 

Second, this also goes against historical examples. The Roman empire had cities that were net mortality sinks that needed constant immigration to succeed. Now, it might be that the overall rate of disease is above some magic threshold but I think the real issue here is that arguments about challenging the immune system only make sense in the context of very mild infections. In the same sense, we would never not treat cholera with antibiotics to allow the immune system to strengthen. A process that strengthens the immune system by killing 50% of victims (e.g., untreated cholera) or 30% of victims (e.g., Variola Major) would need to have immense increase in lifespan as a consequence (it's worse when you consider long term complications). 

Third, the vaccines also stimulate the immune system. If we think that this is the goal, then why would vaccinations (strengthening the immune system at lower risk) not be better than natural infections? 

Central to all of this reasoning is the intuition of relative effect sizes. Vaccines that reduce mortality by huge amounts are simply unlikely to be causing more harm than good. Further, naturalistic ideals don't really account for the shift from low density hunter gatherer situations (much lower burden of disease) to high density urban environments. 

Taken as a whole, vaccines simply look like a super-effective health intervention, even before we consider the network effects.