[Occurrence of Haemophylus influenzae B meningitis after the implementation of a mass vaccination program].

OBJECTIVE To evaluate the incidence of Hib meningitis before and after the implementation of a vaccination program in the state of Rio Grande do Sul State, southern Brazil, in 1999. METHODS This retrospective study summarizes all data concerning Hib meningitis recorded by the state of Rio Grande do Sul Department of Health/Acute Communicable Disease Surveillance Agency between 1995 and 2001. All data were analyzed using the chi-square test (statistical significance: p < 0.005). RESULTS The decline in the number of cases of Hib meningitis was associated with the Hib vaccine coverage in children. From 1995 to 2001 the incidence of Hib meningitis decreased 89% (from 1.35 cases/100,000 people in 1995 to 0.15 cases/100,000 in 2001 (p < 0.01), especially in children younger than 1 year (p < 0.005). In the same period, Hib meningitis lethality decreased from 17.8 to 6.7 % (p < 0.01). CONCLUSIONS The implementation of an Hib meningitis vaccination program has nearly eliminated Hib meningitis in the state of Rio Grande do Sul. These findings underscore the need to maintain the vaccination in children, with a thorough investigation of suspected cases and reporting of confirmed cases.