The reporting of communicable diseases: a controlled study of Neisseria meningitidis and Haemophilus influenzae infections.

Surveillance systems for communicable diseases in the United States are primarily passive. We compared the passive reporting system for invasive disease caused by Neisseria meningitidis and Haemophilus influenzae with a concurrent, active laboratory-based system in the four metropolitan counties of Tennessee. The passive reporting system identified approximately 50% of all cases that were identified by the active system and accurately reflected trends in disease occurrence during the study period. Of all reported cases, physicians contributed fewer than 4%. Nearly 40% of all hospitals in the study area did not participate in the passive system. This lack of participation resulted in disproportionately increased reporting of disease among blacks. Inconsistencies in case definition within the state also contributed substantially to underreporting and lack of demographic representativeness of reported cases. The median reporting interval (the time from the onset of disease to transmission of the case report to the Centers for Disease Control and Prevention) was 24 days (range, 5-157 days). Efforts to improve surveillance of those infections for which isolation of a pathogen is tantamount to a diagnosis should concentrate on laboratory-based reporting and the use of currently available computer telecommunication systems.