Here in San Diego, there were four outbreaks of measles in schoolchildren who were probably not vaccinated from the disease. Here's the story:
http://www.signonsandiego.com/news/metro/20080206-1415-bn06measles.html
Why do parents opt not to vaccinate their kids? Do they fear that their child will become "autistic" from vaccination (where's the connection between the two, anyway)? Do they fear that God would strike them dead if they did so?
Have some common sense. Make your kids get their shots.