Meningococcal disease in Auckland, July 1992 - June 1994.

AIMS

To assess two years of meningococcal disease in the Auckland area, the outcomes and management issues, and the specific socio-geographic groups that are affected.

METHODS

Using the nationally agreed case definition, a retrospective chart review was undertaken. Case finding was through the National surveillance system at ESR, backed by hospital laboratory and coroner case findings.

RESULTS

There were 106 cases of meningococcal disease, both adult and paediatric, from July 1992 to June 1994. Group B (n=61), was predominant throughout this period especially in the winter months. There were two main age groups most affected. The first, and most striking, was in Maori and New Zealand Pacific Island children younger than five years, with rates of 52.6 and 54.2/100,000 respectively. The second peak was in European, and to a lesser extent Maori, 15-24 year-olds, (rates 11.7 and 8.5/100,000, respectively). The annual incidence was 5.6/100,000 with an overall case fatality rate of 6.6%, (n=7). South Auckland had the greatest proportion of cases with 42/106. Two-thirds of the cases were referred for hospital admission by a general practitioner. From both general practitioner and self-referred groups, two-thirds had a petechial/purpuric rash on arrival at hospital. For general practitioner referred cases, 24 received parenteral antibiotics on referral, and from these cases there was one death, (1/24). Those not treated with antibiotics (general practitioner or self-referred) had a mortality of 2/41. There were 31 cases of paediatric meningococcal meningitis. Nineteen cases had dexamethasone in appropriate dose and timing; no hearing loss occurred in the 17 cases that survived (0/17), compared to 2/12 not treated with dexamethasone. This compares to a published rate of 5-7%.

CONCLUSIONS

Meningococcal disease, predominantly serogroup B, is of high incidence in Auckland. The highest rates of disease are occurring in the under five-year-olds, where an effective group B vaccine is awaited. The benefit of dexamethasone is suggestive. There was no clear benefit in outcome by pre-treatment with parenteral antibiotics for paediatric meningococcal disease though no suggestive detrimental effect either.