is one passive data source enough for Haemophilus influenzae?
Background: The completeness of a compulsory reporting system of systemic Haemophilus influenzae infections in children in Germany is studied by means of cross-linking registry data from three sources and applying capture-recapture methods. Methods: Cases were collected for the years 2001–05 by three national data sources: a passive administration registry (SurvNet7commat;RKI), an active hospital surveillance system and an active laboratory surveillance system. The case definition required cultural detection of H. influenzae in blood or cerebrospinal fluid. Linkage was carried out by month and year of birth, sex, geographical region and date of disease onset. Capture-recapture models were used to estimate the incidence of invasive H. influenzae infections. Results: SurvNet7commat;RKI reported 113 H. influenzae and 38 H. influenzae type b (Hib) cases, compared to a total of 231 and 68 cases, respectively, reported by all three sources combined. Best-fitting 3-source capture-recapture es
