title: The association between intentional delay of vaccine administration and timely childhood vaccination coverage.
abstract: OBJECTIVE
  We evaluated the association between intentional delay of vaccine administration and timely vaccination coverage.
  
  
  METHODS
  We used data from 2,921 parents of 19- to 35-month-old children that included parents' reports of intentional delay of vaccine administration. Timely vaccination was defined as administration with > or = 4 doses of diphtheria, tetanus, and pertussis; > or = 3 doses of polio vaccine; > or = 1 dose of measles, mumps, and rubella vaccine; > or = 3 doses of Haemophilus influenzae type b vaccine; > or = 3 doses of hepatitis B vaccine; and > or = 1 dose of varicella vaccine by 19 months of age, as reported by vaccination providers.
  
  
  RESULTS
  In all, 21.8% of parents reported intentionally delaying vaccinations for their children. Among parents who intentionally delayed, 44.8% did so because of concerns about vaccine safety or efficacy and 36.1% delayed because of an ill child. Children whose parents intentionally delayed were significantly less likely to receive all vaccines by 19 months of age than children whose parents did not delay (35.4% vs. 60.1%, p < 0.05). Parents who intentionally delayed were significantly more likely to have heard or read unfavorable information about vaccines than parents who did not intentionally delay (87.6% vs. 71.9%, p < 0.05). Compared with parents who intentionally delayed only because their child was ill, parents who intentionally delayed only because of vaccine safety or efficacy concerns were significantly more likely to seek additional information about their decision from the Internet (11.4% vs. 1.1%, p < 0.05), and significantly less likely to seek information from a doctor (73.9% vs. 93.9%, p < 0.05).
  
  
  CONCLUSIONS
  Intentionally delayed vaccine doses are not uncommon. Children whose parents delay vaccinations may be at increased risk of not receiving all recommended vaccine doses by 19 months of age and are more vulnerable to vaccine-preventable diseases. Providers should consider strategies such as educational materials that address parents' vaccine safety and efficacy concerns to encourage timely vaccination.
authors.affiliation: Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Disease, Atlanta, GA 30333, USA. pzs6@cdc.gov
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Smith
authors.forename: Sharon G
authors.initials: SG
authors.lastname: Humiston
authors.forename: Trish
authors.initials: T
authors.lastname: Parnell
authors.forename: Kirsten S
authors.initials: KS
authors.lastname: Vannice
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Salmon
mesh_terms: D000328:Adult; D002675:Child, Preschool; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage; D005260:Female; D019538:Health Care Surveys; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage; D010290:Parents / Q000523:psychology*; D010342:Patient Acceptance of Health Care / Q000523:psychology; D023321:Poliovirus Vaccines / Q000008:administration & dosage; D012449:Safety; D013997:Time Factors; D016312:Treatment Refusal / Q000523:psychology; D014481:United States; D014611:Vaccination / Q000523:psychology*; D055815:Young Adult
chemical_list: D015721:Diphtheria-Tetanus-Pertussis Vaccine; D022542:Measles-Mumps-Rubella Vaccine; D023321:Poliovirus Vaccines