1. The childhood diseases that are prevented by immunization are easily communicable.
2. No vaccine is 100% effective.
3. Very few vaccines work for longer than 20 years.
4. Many of these diseases can have catastrophic effects on children. Some of them even on adults.
5. Children who have not been vaccinated are a reservoir and vector of infection.
6. Thus, to not vaccinate your children is to increase the health risk for the population at large.
6a. The recent spread of measles (or perhaps mumps, I forget which) in Britain in the wake of the now-discredited autism scare suggests that even a small reduction in the percentage of children vaccinated can radically increase the incidence of a given disease.
7. Thus the state, in its role of preventing epidemic disease has a perfect right to ensure that people receive vaccines.
8. Further, given point 6a, a relatively small number of objectors can raise risk dramatically, compulsion is in order.

Now, for isolated religious communities (I’m largely thinking the stereotypical Amish), this may not be a problem since they do not interact with society at large often enough to pose a substantial risk. However, even home-schooled children have public interactions (the library, dance lessons, soccer practice, the park, etc.) and thus are liable to spread airborne disease.

1. The childhood diseases that are prevented by immunization are easily communicable.
2. No vaccine is 100% effective.
3. Very few vaccines work for longer than 20 years.
4. Many of these diseases can have catastrophic effects on children. Some of them even on adults.
5. Children who have not been vaccinated are a reservoir and vector of infection.
6. Thus, to not vaccinate your children is to increase the health risk for the population at large.
6a. The recent spread of measles (or perhaps mumps, I forget which) in Britain in the wake of the now-discredited autism scare suggests that even a small reduction in the percentage of children vaccinated can radically increase the incidence of a given disease.
7. Thus the state, in its role of preventing epidemic disease has a perfect right to ensure that people receive vaccines.
8. Further, given point 6a, a relatively small number of objectors can raise risk dramatically, compulsion is in order.

Now, for isolated religious communities (I’m largely thinking the stereotypical Amish), this may not be a problem since they do not interact with society at large often enough to pose a substantial risk. However, even home-schooled children have public interactions (the library, dance lessons, soccer practice, the park, etc.) and thus are liable to spread airborne disease.