Invasive meningococcal disease in Maricopa County Arizona 2000-2006

Background:Neisseria meningitidis is the leading cause of bacterial meningitis in children and young adults in the US. Invasive meningococcal disease (IMD) is associated with substantial morbidity and mortality. In this study, surveillance data on IMD in Maricopa County Arizona was evaluated with subsequent assessment of disease trends. Methods: Data reported to Maricopa County Department of Public Health on IMD from 1/1/2000 to 6/30/2006 was evaluated to determine incidence, epidemiologic characteristics, and serogroup patterns of disease in Maricopa County. Cases from 1/1/2005-6/30/2006 were additionally evaluated for timeliness of reporting and investigation. Results: 113 cases of IMD were identified during the study period. Incidence of IMD declined from 2000-2006. Median incidence rate was 0.5. Overall case fatality rate was 11%. A higher proportion of cases occurred in the winter and early spring months. 42% (n=47) of IMD cases were caused by vaccine-preventable serogroups. Rate of disease caused by vaccine-preventable serogroups was higher in the Hispanic population. Overall rate of disease declined between 2000-2006 in the 0-4 year old and Hispanic populations. 48% (n=13) of IMD cases in the data subset were reported ≥3 days after obtaining cultures. Conclusion: This study provides baseline epidemiologic trends of IMD in Maricopa County. The tetravalent meningococcal conjugate vaccine is currently available and recommended for routine immunization of 11-12 year olds, catch-up at 15 years or prior to college. Subsequent evaluation of surveillance data on IMD in Maricopa County can assess the effect of routine meningococcal vaccination. Timeliness of reporting warrants further investigation.