title: Impact of Haemophilus influenzae type b conjugate vaccine on bacterial meningitis in the Dominican Republic.
abstract: OBJECTIVE
  Widespread use of Haemophilus influenzae type b (Hib) vaccines has dramatically reduced the burden of Hib disease throughout the Americas. Few studies have evaluated the impact of Hib vaccination on non-culture-confirmed disease. This study analyzed trends in probable bacterial meningitis before and after the introduction of Hib vaccine in the Dominican Republic and estimated vaccine effectiveness against Hib meningitis.
  
  
  METHODS
  Meningitis cases among children < 5 years of age were identified from admission records of the main pediatric hospital in Santo Domingo during 1998-2004. Laboratory criteria were used to classify meningitis cases with probable bacterial etiology; confirmed cases had positive bacterial culture or antigen detection in cerebrospinal fluid. Cumulative incidence rates of confirmed and probable bacterial meningitis were calculated for children living in the National District. Confirmed cases of Hib meningitis were enrolled in a case-control study with age- and neighborhood-matched control children to calculate vaccine effectiveness.
  
  
  RESULTS
  Before vaccine introduction, annual rates of meningitis with probable bacterial etiology were 49 cases per 100 000 children < 5 years old; Hib accounted for 60% of confirmed bacterial cases. During 2002-2004, after vaccine introduction, annual rates of probable bacterial meningitis were 65% lower at 16 cases per 100 000, and Hib accounted for 26% of confirmed cases. Rates of Hib meningitis and probable bacterial meningitis with no determined etiology declined by 13 and 17 cases per 100 000, respectively.
  
  
  CONCLUSIONS
  Introduction of Hib vaccine substantially reduced the incidence of confirmed and probable bacterial meningitis in the Dominican Republic. The estimated impact of Hib vaccination was twice as great when non-culture-confirmed disease was included.
authors.affiliation: Division of Bacterial Diseases, National Center for Immunizations and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. ellelee@hotmail.com
authors.forename: Ellen H
authors.initials: EH
authors.lastname: Lee
authors.forename: Miriam
authors.initials: M
authors.lastname: Corcino
authors.forename: Arelis
authors.initials: A
authors.lastname: Moore
authors.forename: Zacarias
authors.initials: Z
authors.lastname: Garib
authors.forename: Chabela
authors.initials: C
authors.lastname: Peña
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Sánchez
authors.forename: Josefina
authors.initials: J
authors.lastname: Fernández
authors.forename: Jesús M
authors.initials: JM
authors.lastname: Feris-Iglesias
authors.forename: Brendan
authors.initials: B
authors.lastname: Flannery
mesh_terms: D016667:Bacterial Capsules / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D004293:Dominican Republic / Q000453:epidemiology; D018073:Haemophilus Vaccines / Q000008:administration & dosage*; D019741:Haemophilus influenzae type b / Q000302:isolation & purification*; D006801:Humans; D008583:Meningitis, Haemophilus / Q000453:epidemiology* / Q000382:microbiology*
chemical_list: D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine