Just replying to the OP:
I took an Epidemiology class in graduate school and we watched this really cool (old) video from the BBC about Bangladesh's small pox vaccination campaign. They hired community health workers to go out to specific communities and vaccinate as many people as they could. Surveillance was key because there was no way that every person could be vaccinated- when they found a case, they vaccinated "rings" to create a herd. They showed how this created a "ring" of immunity. Their efforts were successful, of course.
I wish this was an easily accessible video. It was a really clear introduction to the concept of herd immunity. I'm pretty sure the Prof had it on VHS so I doubt that it's easily available.
So, yes, I absolutely think that the science behind herd immunity is valid. There are many other examples of vaccines being introduced in similar ways and seeing major declines in disease incidence.
I think in this discussion, there are some issues with some people coming to the table with varied knowledge about certain diseases and vaccines. Not all diseases have vaccines and vaccines aren't totally effective. These facts don't negate the salience of vaccinations.
Edited by freestylemama - 7/12/11 at 1:37pm