Where states significantly differ is in their recognition of exemptions from vaccination.
Besides specific vaccine requirements, these schedules may also refer to the schedules provided by the United States Department of Health and Human Services, American Academy of Family Physicians, or American Academy of Pediatrics. For each state, the immunization schedule may be found in the state code or its administrative regulations, usually in the sections governing education (for schools) or public health (for child care facilities). All states require children to be immunized or to be in the process of receiving immunizations against certain contagious diseases before a child care facility or a school may admit them.