8784b9b1_unization_policy_for_providers__How_Often
[Immunization] Polio [Why] Polio attacks the nervous system and can cause paralysis in legs or other areas. When children are vaccinated using live polio vaccine, they may shed live polio vaccine virus in their feces or urine for several weeks after receiving the vaccine. Very rarely, the vaccine virus can change into a more dangerous form and cause paralytic polio. Anyone who is in frequent contact with recently vaccinated children, especially changing diapers, should be certain she or he has been vaccinated against polio. [How Often] 
Child care providers, especially those working with children who are not toilet-trained, should have a record of a primary series of 3 doses (usually given in childhood) and a supplementary dose given at least 6 months after the third dose in the primary series.
Health History and immunization policy for providers
How Often