title: The effectiveness of conjugate Haemophilus influenzae type B vaccine in The Gambia 14 years after introduction.
abstract: BACKGROUND
  The Gambia was the first country in Africa to introduce conjugate Haemophilus influenzae type b (Hib) vaccine, which, as in other developing countries but unlike industrialized countries, is delivered as a 3-dose primary series with no booster. This study assessed its effectiveness 14 years after introduction.
  
  
  METHODS
  Using methods standardized during >20 years in the study site, clinical and microbiological surveillance for invasive Hib disease (primarily meningitis) in the Western Region of The Gambia from 2007 to 2010 was complemented with studies of Hib carriage in children aged 1 to <2 years, Hib antibody levels in children aged <5 years, and Hib vaccine coverage and timing in children aged 1 to <2 years.
  
  
  RESULTS
  The incidence of Hib meningitis remained low (averaging 1.3 per 100 000 children aged <5 years annually), as did the Hib oropharyngeal carriage rate (0.9%). Hib antibody levels were protective in >99% of those surveyed, albeit with lower titers in older children; and coverage of conjugate Hib vaccination was high (91% having 3 doses at 1-2 years of age) using a schedule that was delivered at median ages of 2.6 months, 4.3 months, and 6 months for the first, second, and third doses, respectively.
  
  
  CONCLUSIONS
  Conjugate Hib vaccine was delivered on time in a 3-dose primary series without booster to a high proportion of eligible children and this was associated with effective disease control up to 14 years after introduction. It is important that surveillance continues in this first African country to introduce the vaccine to determine if effective control persists or if a booster dose becomes necessary as has been the case in industrialized countries.
authors.affiliation: Child Survival Theme.
authors.forename: Stephen R C
authors.initials: SR
authors.lastname: Howie
authors.forename: Claire
authors.initials: C
authors.lastname: Oluwalana
authors.forename: Ousman
authors.initials: O
authors.lastname: Secka
authors.forename: Susana
authors.initials: S
authors.lastname: Scott
authors.forename: Readon C
authors.initials: RC
authors.lastname: Ideh
authors.forename: Bernard E
authors.initials: BE
authors.lastname: Ebruke
authors.forename: Anne
authors.initials: A
authors.lastname: Balloch
authors.forename: Sana
authors.initials: S
authors.lastname: Sambou
authors.forename: James
authors.initials: J
authors.lastname: Erskine
authors.forename: Yamundow
authors.initials: Y
authors.lastname: Lowe
authors.forename: Tumani
authors.initials: T
authors.lastname: Corrah
authors.forename: Richard A
authors.initials: RA
authors.lastname: Adegbola
mesh_terms: D002353:Carrier State / Q000453:epidemiology; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005714:Gambia / Q000453:epidemiology; D006192:Haemophilus Infections / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D018073:Haemophilus Vaccines / Q000008:administration & dosage* / Q000276:immunology; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D007223:Infant; D032541:Mass Vaccination; D062486:Public Health Surveillance; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D018073:Haemophilus Vaccines; D018074:Vaccines, Conjugate
keywords: Africa; Gambia; Hib disease; Hib vaccination; surveillance
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