My first impulse is to agree with those who have made the decision to avoid vaccines for their children. *But I can't help but feel that these children are only safe because everyone else around them is vaccinated, ensuring they'll never get exposed to these viruses/germs.* But what happens if the number of unvaccinated children rises in the future? Other than smallpox, none of these diseases has really been eradicated. So if no-one is vaccinated, everyone becomes vulnerable. Has the anti-vax movement addressed these questions effectively? Cheyenne Vaccines contain the germ for which they are "immunizing" against. So, when an unvaccinated child is exposed to a recently-vaccinated child, he is then exposed to the germ. Those who do not vaccinate their children will want to try to keep them away from recently vaccinated children. (Polio is one of the most notorious diseases which can be spread this way.) There is concern among those who oppose vaccine that the vaccinations themselves are responsible for more cases of the disease than it prevents.