title: Potential link between rates of childhood  vaccination exemptions and state opt-out  procedures.
authors.forename: Jenaid
authors.initials: J
authors.lastname: Rees
mesh_terms: D000293:Adolescent; D002648:Child; D006291:Health Policy; D006801:Humans; D017589:Immunization Programs; D014481:United States; D014611:Vaccination / Q000379:methods* / Q000706:statistics & numerical data*