title: Completion and compliance of childhood vaccinations in the United States.
abstract: BACKGROUND
  The Advisory Committee on Immunization Practices recommends routine childhood vaccination by age 2 years, yet evidence suggests that only 2% to 26% of children receive vaccine doses at age-appropriate times (compliance). The objective of this study was to estimate vaccine completion and compliance rates between birth and age 2 years using recent, nationally representative data.
  
  
  METHODS
  Using a sample of children aged 24 to 35 months from the 2012 National Immunization Survey (NIS), the present study examined completion and compliance of recommended childhood vaccines. A state-specific examination of vaccine completion and compliance was also conducted.
  
  
  RESULTS
  An unweighted sample of 11,710 children (weighted to 4.1 million) was selected. Approximately 70% of children completed all doses of six recommended vaccines by 24 months of age. Completion rates varied by antigen, ranging from 68% completing two or three doses of rotavirus vaccine to 92% completing three doses of inactivated poliovirus vaccine. Vaccine completion rates also varied at different measurement periods, with the lowest rates observed at 18 months. Approximately 26% of children received all doses of six recommended vaccines on time. Among the 74% of children who received at least one late dose, 39% had >7 months of undervaccination. Patterns of completion and compliance also varied by geographic region.
  
  
  CONCLUSIONS
  Completion of individual antigens approached Healthy People 2020 targets. However, overall completion of the recommended vaccine series and compliance with the recommended vaccination dosing schedule were low, indicating few children received vaccines at age-appropriate times. Additional clinical, policy, and educational interventions are needed to increase receipt of vaccines at optimal ages.
authors.affiliation: RTI Health Solutions, 200 Park Offices Drive, PO Box 12194, Research Triangle Park, NC 27709, USA. Electronic address: skurosky@rti.org.
authors.forename: Samantha K
authors.initials: SK
authors.lastname: Kurosky
authors.affiliation: RTI Health Solutions, 200 Park Offices Drive, PO Box 12194, Research Triangle Park, NC 27709, USA. Electronic address: kldavis@rti.org.
authors.forename: Keith L
authors.initials: KL
authors.lastname: Davis
authors.affiliation: GSK, 5 Crescent Drive, Philadelphia, PA 19112, USA. Electronic address: girishanthy.x.krishnarajah@gsk.com.
authors.forename: Girishanthy
authors.initials: G
authors.lastname: Krishnarajah
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence; D010349:Patient Compliance; D014481:United States; D014611:Vaccination / Q000706:statistics & numerical data*; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D014612:Vaccines
keywords: ACIP; Immunisation; Timeliness; Undervaccination