title: Timeliness of childhood immunizations.
abstract: OBJECTIVE
  To examine the timeliness of vaccine administration among infants and young children in the United States.
  
  
  METHODS
  We analyzed age at receipt of vaccines among 16 211 children aged 24 to 35 months in the 2000 National Immunization Survey and examined receipt at the recommended time of each dose and selected vaccination series, as well as receipt at 4 additional time frames: acceptably early, late, never by 24 months, and too early to be considered valid. We also examined the relationship between timeliness of vaccinations and characteristics of the child, mother, and immunization provider, using multivariate logistic regression.
  
  
  RESULTS
  Only 9% of children received all recommended vaccines at the recommended ages. The rates varied significantly by antigen, ranging from 24% for all Haemophilus influenzae type b doses to 75% for all hepatitis B doses as recommended. Overall, 55% of children did not receive all recommended doses by 24 months of age, and 8% of children received at least 1 vaccination dose too early to be considered valid. Factors associated with not receiving all vaccines as recommended were having more children in the household, mothers younger than 30 years, use of public providers, and multiple vaccination providers.
  
  
  CONCLUSIONS
  By 24 months of age, 9 of 10 children received at least 1 vaccine outside the recommended age ranges. High vaccination status of children at 24 months of age does not reflect the reality that many vaccinations are not given at the appropriate ages. Timeliness of vaccination is critical to prevent disease outbreaks, protect children through their first 2 years of life, and minimize the need to repeat doses.
authors.affiliation: National Immunization Program, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. ecl7@cdc.gov
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Luman
authors.forename: Mary Mason
authors.initials: MM
authors.lastname: McCauley
authors.forename: Shannon
authors.initials: S
authors.lastname: Stokley
authors.forename: Susan Y
authors.initials: SY
authors.lastname: Chu
authors.forename: Larry K
authors.initials: LK
authors.lastname: Pickering
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005260:Female; D019538:Health Care Surveys / Q000706:statistics & numerical data; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D010372:Pediatrics / Q000706:statistics & numerical data; D014481:United States; D014611:Vaccination / Q000592:standards / Q000706:statistics & numerical data*; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D014612:Vaccines