Invasive Haemophilus influenzae type b infections in Singapore children: Ahospital-based study

Objective: A 6-year (1990-95) hospital-based retrospective study was carrie d out to investigate the pattern of invasive Haemophilus influenzae type b (Hib) disease. Methodology: Cases with Hib isolated from sterile sites (blood, cerebrospin al fluid, or joint aspirate) were identified from the hospital's microbiolo gical records, and their reviewed case records. Patients with pyogenic meni ngitis in the same study period were also identified to estimate the incide nce of Hib meningitis. Results: Twelve patients had positive cultures from sterile sites, of whom nine children were less than 5 years of age These included seven cases of m eningitis, one patient with acute epiglottitis, and one case of pneumonia. Three of the seven patients with meningitis had significant long-term seque lae. Our data also suggests a relatively low proportion of ethnic Chinese c hildren with invasive disease. It was estimated that 18.4% to 41.1% of pyog enic meningitis in children admitted to the National University Hospital we re due to Hib. The estimated annual attack rate of invasive Hib disease was at most 3.3 per 100 000 children aged less than 5 years (95% confidence in terval: 2.6-3.5/100 000). Conclusion: Invasive Hib infections are relatively uncommon in our communit y. This justifies the need for a cost effectiveness study before a universa l Hib vaccination program is implemented.