title: [Impact of Haemophilus influenzae b (Hib) vaccination on meningitis in Central Brazil].
abstract: OBJECTIVE
  To assess the impact of the Haemophilus influenzae b (Hib) conjugate vaccine in reducing the incidence of meningitis among children under five years old.
  
  
  METHODS
  A 'before-after' design was used to compare Hib meningitis incidence rates in the pre-vaccine (July 1995 - June 1999) and post-vaccine (July 1999 - June 2001) periods in the state of Goias, central Brazil. Bacterial meningitis case definition was based on World Health Organization criteria. Incidence rates of S. pneumoniae and N. meningitidis were used for comparison purposes. Chi-squared and Student's t tests were used for statistical analysis. P-values below 0.05 were considered as statistically significant.
  
  
  RESULTS
  979 children with acute bacterial meningitis were detected throughout the entire period. The incidence rate of Hib meningitis decreased from 10.8 (x10(5)) in the pre-vaccine period to 2.3 (x10(5)) in the 2nd year post vaccination, leading to a risk reduction of 78%, targeted to the 7-23 months age group (p<0.05). A total of 65 cases of Hib meningitis were prevented. An increase in S. pneumoniae meningitis was observed. Vaccine failure was detected in one child.
  
  
  CONCLUSIONS
  This study showed that mass immunization with Hib conjugate vaccine brought about an expressive decline in childhood Hib meningitis in Goias soon after the first year. Notwithstanding, an enhancement of surveillance using high-accuracy tools is essential to: (i) detect a possible reemergence of Hib; (ii) identify vaccine failure, and (iii) monitor changes in the H. influenzae serotype profile over time.
authors.affiliation: Hospital de Doenças Tropicais, Goiânia, GO, Brazil. pineli@doutor.com.br
authors.forename: Luciana Leite Pineli
authors.initials: LL
authors.lastname: Simões
authors.forename: Ana Lúcia S S
authors.initials: AL
authors.lastname: Andrade
authors.forename: Cristina A
authors.initials: CA
authors.lastname: Laval
authors.forename: Renato M
authors.initials: RM
authors.lastname: Oliveira
authors.forename: Simmone A
authors.initials: SA
authors.lastname: Silva
authors.forename: Celina M T
authors.initials: CM
authors.lastname: Martelli
authors.forename: Sueli L de A
authors.initials: SL
authors.lastname: Alves
authors.forename: Robmary M
authors.initials: RM
authors.lastname: Almeida
authors.forename: João G
authors.initials: JG
authors.lastname: Andrade
mesh_terms: D001938:Brazil / Q000453:epidemiology; D002675:Child, Preschool; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage*; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008583:Meningitis, Haemophilus / Q000453:epidemiology* / Q000517:prevention & control; D013745:Tetanus Toxoid / Q000008:administration & dosage*; D018074:Vaccines, Conjugate / Q000008:administration & dosage
chemical_list: D018073:Haemophilus Vaccines; C055753:Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate