While all 50 states allow exemptions for children who have a valid medical reason, and almost all states
allow nonmedical exemptions for parents with either religious or philosophical objections, the political climate has recently shifted in favor of making exemptions more difficult to obtain.
As of March 2006, all states permitted medical
exemptions to school and daycare immunization requirements; 48 states
allowed religious
exemptions; and 19 states had a provision for personal belief
exemptions, such as religious, philosophical, and any other unspecified
nonmedical exemption.