The U.S. medical system does a good job of vaccinating children. The CDC has a list of recommended vaccinations which most children receive during routine physician visits. As children grow into adolescents, however, they are less likely to visit their primary care provider regularly. As a handful of new vaccines are targeted at teens (e.g., vaccines against meningococcal meningitis), the CDC is trying to target to teens using in-school vaccinations.
Reactions to this policy depends on whether you believe these vaccines provide more health benefits than risks (which I and most researchers do) or if you believe the risks of illness outweighs the health benefits.
Below are two headlines describing the same pilot in-school vaccination program in Denver.