[Haemophilus influenza type b invasive disease in the Community of Valencia. Study Group on Invasive Diseases]

The objective of this study was to estimate the incidence of systemic Haemophilus influenzae type b (Hib) disease in the Valencian Community, Spain, and to study the microbiological characteristics of the strains. Prospective, active surveillance of children in the Valencian Community. Data were obtained from microbiology laboratories and paediatricians. A case was considered when a child younger than 15 years of age had clinical invasive disease and a Haemophilus influenzae (Hi) was isolated from a normally sterile site, or when a positive capsular antigen was identified with a compatible Gram strain. In the first year of surveillance, starting on December 1, 24 cases were identified. Of the 20 strains studied in our laboratory, 19 were serotype b and one non typable. 75% of the strains were beta-lactamase positive. Meningitis was the most frequent clinical presentation. All children were less than five, and 51.2% were less than one year of age. The mortality was 8.3%. For unvaccinated children less than 5 years the estimated incidence of invasive disease was 18.2/100,000 and of meningitis 14.0/100,000. The incidence of Hib invasive disease in unvaccinated children justifies the universal Hib vaccine programme in the Valencian Community.