title: The use of combination vaccines has improved timeliness of vaccination in children.
abstract: BACKGROUND
  In Germany, Haemophilus influenzae type b (Hib), polio and hepatitis B (HBV) vaccines have been combined with diphtheria, tetanus and acellular pertussis vaccines. We examined whether the use of combination vaccines has improved the timing of these vaccinations.
  
  
  METHODS
  Vaccination information was obtained from representative nationwide telephone interviews about 2701 children born from 1996 through 2003 in Germany. We assessed up-to-date vaccination as the percentage of children vaccinated by 3, 5 and 15 months for the first dose, full primary series and full immunization, respectively. We compared results over periods when different combination vaccines were used. We also compared median age at first dose, full priming and full immunization for children receiving different types of combination vaccines.
  
  
  RESULTS
  During the study period, monovalent vaccines were replaced by higher-valent combination vaccines. With the change from mono- to 4-, 5- and 6-valent vaccines, up-to-date vaccination increased for Hib, polio and HBV. Median age at immunization improved by 0.5 month for Hib, 0.4 month for polio and 0.9 month for HBV at the first dose and 2.2 months for Hib, 3.2 months for polio and 1.4 months for HBV at full immunization when comparing hexavalent with monovalent vaccines. Median age for 4-5-valent vaccines was intermediate. The difference between monovalent and 6-valent vaccines remained significant after stratifying/adjusting for the effect of birth cohorts.
  
  
  CONCLUSIONS
  Combination vaccines are usually advocated for reducing the number of injections. In Germany, however, the use of combination vaccines has also significantly improved timeliness of immunizations.
authors.affiliation: Department of Pediatric Epidemiology, Institute for Social Pediatrics and Adolescent Medicine of Ludwig-Maximilians-University, Munich, Germany. kalies@uni-muenchen.de
authors.forename: Helen
authors.initials: H
authors.lastname: Kalies
authors.forename: Veit
authors.initials: V
authors.lastname: Grote
authors.forename: Thomas
authors.initials: T
authors.lastname: Verstraeten
authors.forename: Luc
authors.initials: L
authors.lastname: Hessel
authors.forename: Heinz-Josef
authors.initials: HJ
authors.lastname: Schmitt
authors.forename: Rüdiger
authors.initials: R
authors.lastname: von Kries
mesh_terms: D002675:Child, Preschool; D003430:Cross-Sectional Studies; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines / Q000008:administration & dosage*; D005260:Female; D005858:Germany; D018073:Haemophilus Vaccines / Q000008:administration & dosage*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007109:Immunity / Q000502:physiology; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D018570:Risk Assessment; D011795:Surveys and Questionnaires; D013997:Time Factors; D014611:Vaccination / Q000592:standards* / Q000639:trends; D017778:Vaccines, Combined / Q000008:administration & dosage*
chemical_list: D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines; D018073:Haemophilus Vaccines; D017325:Hepatitis B Vaccines; D017778:Vaccines, Combined