Bacterial meningitis in children under five years of age in Western Australia.

OBJECTIVES

To describe the epidemiology and the associated mortality and serious neurological sequelae of bacterial meningitis in children under five years of age in Western Australia, and to consider the potential impact of a Haemophilus influenzae type b vaccine on this group of children.

DESIGN

A retrospective survey, using multiple sources of case ascertainment.

PATIENTS

All children in Western Australia from one month to five years of age who developed bacterial meningitis, over a five-year period (from 1984 to 1988 inclusive).

MAIN OUTCOME MEASURES

Episodes of bacterial meningitis, deaths associated with bacterial meningitis, and sensorineural deafness (requiring hearing aids) and cerebral palsy following bacterial meningitis.

RESULTS

Two hundred and seventy episodes of bacterial meningitis were identified; 200 occurred in non-Aboriginal children and 70 in Aboriginal children. There were 16 meningitis-associated deaths (case fatality rate, 5.9%), 7 children developed profound sensorineural deafness and a further 7 children developed cerebral palsy after bacterial meningitis. H. influenzae type b caused nearly 70% of the cases of childhood bacterial meningitis. The annual incidence rate of H. influenzae meningitis was significantly greater in Aboriginal children (150 episodes per 100,000 children under five years of age per year) than in non-Aboriginal children (27 episodes per 100,000), and the mean age of onset of H. influenzae meningitis was significantly lower in Aboriginal children (6.8 months) than in non-Aboriginal children (19.8 months).

CONCLUSIONS

Any conjugate H. influenzae type b vaccine should be effective when administered to non-Aboriginal children in the first six months of life, but only the most immunogenic vaccines (for example, the vaccine known as PRP-OMP) are likely to be effective in Aboriginal infants.