A descriptive report of invasive Haemophilus influenzae cases as reported to the Maricopa County Department of Public Health. The purpose of this report is twofold: first to define the illness and its trends in Maricopa County during this time period and second to identify potential areas of improvement in data quality.

This study provides useful information for the Office of Epidemiology on reporting, investigating, and data completeness. Reporting of cases occurred ≥ 3 days in about 50% of the cases, despite a 24 hour reporting mandate for cases or suspect cases. Data can be analyzed on a yearly basis using this study as a model. Future analyses can reassess the epidemiologic trends noted in this study and assess the effect of routine meningococcal vaccination in Maricopa County.