[Relevance of sentinel surveillance systems for the implementation and evaluation of vaccination strategies].

In sentinel surveillance a prearranged sample of reporting sources-often healthcare providers-agrees to report all cases of defined conditions. The German "Protection Against Infection Act" (IfSG) provides a mandate to the Robert Koch-Institute (RKI) to establish sentinel surveillance of not notifiable diseases relevant to public health. Sentinel systems with RKI involvement include two networks of private practitioners reporting cases of influenza and measles (within the Working Groups on Influenza and Measles, respectively). In addition a laboratory-based sentinel system reports cases of certain bacterial infections in children. Results from these systems serve as a basis for framing vaccination recommendations and goals as well as for the evaluation, adjustment and promotion of vaccination strategies. The data indicate time trends (e. g. number of cases by season, age and region) and supply specific information (e. g. for determination of risk factors, distribution of pathogens). Methodological problems of sentinel surveys (e. g. selection of appropriate samples, population-based estimates) can be accounted for with appropriate methods of analysis. More effective implementation of sentinel surveillance in Germany could be achieved through better coordination of existing structures. This would make more effective use of limited resources and better enable timely and flexible investigation of conceptual and organisational questions.