title: Potential for improving age-appropriate vaccination coverage by maximizing the 18-month well-child visit.
abstract: OBJECTIVE
  To evaluate potential age-appropriate up-to-date (UTD) vaccination coverage achievable in preschool children if missing vaccinations were administered during a well-child visit at 18 months of age.
  
  
  METHODS
  Data from the 2004 National Immunization Survey were used in a series of simulations analyzing UTD coverage of the 4:3:1:3:3:1 (diphtheria, tetanus, pertussis/poliovirus/measles-containing vaccine/Haemophilus influenzae type b/hepatitis B/varicella) and 4:3:1:3:3:1 (+) pneumococcal conjugate vaccine (PCV) series. In the models, children not already up-to-date received up to four missing vaccinations during a simulated routine 18-month-old well-child visit.
  
  
  RESULTS
  For the 4:3:1:3:3:1 series, UTD coverage increased from baseline 61 percent (95% confidence interval [CI] = 60-62) to simulated 87 percent (95% CI = 86-88). Among the baseline non-UTD children, 69 percent became up-to-date by simulation with the single visit, of which 44 percent required only one vaccination. For the 4:3:1:3:3:1 (+) PCV series, UTD coverage increased from baseline 38 percent (95% CI = 37-40) to simulated 74 percent (95% CI = 73-75). Among the baseline non-UTD children, 59 percent became up-to-date by simulation with the single visit, of which 47 percent required only one vaccination. UTD coverage increased substantially for all racial/ethnic groups and in all states.
  
  
  CONCLUSIONS
  Taking full advantage of the recommended 18-month-old well-child visit to administer missing vaccines would be a strategically timed opportunity to achieve high age-appropriate UTD coverage in preschool children.
authors.affiliation: Health Services Research and Evaluation Branch, Immunization Services Division, National Center for Immunization and Respiratory Diseases, CDC, Atlanta, Georgia 30333, USA. TShimabukuro@cdc.gov
authors.forename: Tom T
authors.initials: TT
authors.lastname: Shimabukuro
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Luman
authors.forename: Carla A
authors.initials: CA
authors.lastname: Winston
authors.forename: Richard A
authors.initials: RA
authors.lastname: Schieber
mesh_terms: D000367:Age Factors; D002662:Child Health Services / Q000458:organization & administration* / Q000706:statistics & numerical data; D005006:Ethnicity; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D044469:Racial Groups; D013997:Time Factors; D014611:Vaccination; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D014612:Vaccines