Epidemiology of Haemophilus influenzae type b meningitis in Manila, Philippines, 1994 to 1996.

BACKGROUND: Effective vaccines against Haemophilus influenzae type b (Hib) have shown impressive results in decreasing Hib meningitis in developed countries. In the Philippines Hib vaccines are not part of the routine immunization given to children. Before a decision can be made to include Hib vaccines in immunization program, epidemiology of Hib meningitis in Manila, Philippines, should first be described.

METHODOLOGY: A cohort of 41,592 children <5 years of age in Central Manila was the study population. Confirmed cases between January, 1994, and December, 1996, were obtained from all hospitals in the region. Confirmation of cases was based on positive culture isolated from blood or cerebrospinal fluid (CSF) or Hib antigen identified in CSF with a clinical diagnosis of Hib meningitis. The progress of children with Hib meningitis postinfection was evaluated from hospital records.

RESULTS: There were 118 episodes of Hib meningitis identified in the population in the study period. Sequelae occurred in 15% of the total cases, and the case fatality rate was 11%. The annual incidence of Hib meningitis in Manila for children <5 years old was 95 per 100,000.

CONCLUSIONS: Hib meningitis in Central Manila is common. The incidence is particularly high in children <6 months old. Adverse neurologic outcomes and a high case fatality rate in children younger than 1 year suggest that a vaccination program would be useful.