[tcj_phx]

Measles is one of the diseases that you only get once, then you're immune for the rest of your life. Some kids are killed by measles, which is why the vaccine is popular - it is difficult to predict which kids will have a difficult case of teh measles.

[baq]

It's worse. Some kids can't be vaccinated for whatever reasons. They piggyback on others. If you take the herd immunity from their society, you put them in grave danger.

[laughfactory]

Plus, some outbreaks happen even in vaccinated communities. There aren't many people who are totally against vaccines. Most just recognize that hitting kids with the recommended onslaught of vaccines is associated with a higher percentage of kids suddenly mentally handicapped or dead or paralyzed. Vaccines are often beneficial, but they're not risk free.