Incidence of invasive pneumococcal disease in Sydney children, 1991-96

Objective: Few data are available on invasive disease due to Streptococcus pneumoniae in representative Australian childhood populations. This study a imed to determine the age-specific incidence of invasive pneumococcal disea se in Sydney children. Methodology: Population-based prospective study where isolates of Streptoco ccus pneumoniae from normally sterile sites were identified through an esta blished laboratory surveillance network. Isolates came from children aged u nder 15 years living within the boundaries of Central, Eastern, Southern, W estern and South-western Sydney Area Health Services from 1 July 1991 to 30 June 1996. Results: Invasive pneumococcal disease was identified in 320 children durin g a 5-year period, of whom 193 (60%) were under 2 years of age. The inciden ce per 100 000 children was 12.7 per 100 000 (95% CI: 11.4-14.2/100 000) un der 15 years; 31.7 (95% CI 28.1-35.7) under 5 years, and 45.5 (95% CI 38.9- 53.3) under 2 years. The incidence of pneumococcal meningitis in children a ged under 2 years was 10.5 per 100 000 (95% CI: 7.4-14.5/100 000). Conclusions: The incidence of childhood invasive pneumococcal disease in Sy dney was stable during 1991-96 and comparable to rates reported from other industrialized countries. There was no evidence of any change in pneumococc al disease incidence with reduction in invasive Haemophilus influenzae type b (Hib) disease following introduction of Hib immunization.