Confirmation diagnosis of influenza A(H1N1)2009 by Belgian sentinel laboratories during the epidemic phase

Because of the high amount of these requests, it was proposed to decentralise the diagnostic capacity from the Belgian National Influenza Centre (NIC) to a network of 'partner' laboratories. [...]all sentinel laboratories were invited to implement the diagnostic tests, to participate in epidemiological surveillance in the frame of the sentinel laboratory network, to participate in virological surveillance by sending laboratory results or strains to be further subtyped at the NIC. Two laboratories, one from the Flemish region and one from the Brussels-Capital Region, received together 3190 out of the 5942 samples (53.7%). Since the majority of the laboratories reporting the postal code were localised in the Flemish Region (n = 6) and in Brussels (n = 2), samples were mainly collected from patients from these regions: 3159 from Flemish region, 1403 from Brussels, 898 from the Walloon region and 482 patients with unknown residence. The missing information for gender, residence and date of birth can be explained by the priorities defined by the individual laboratories. [...]the decentralisation reduced the capacity and the power of the epidemiological surveillance and this information can only be provided by community-based surveillance programmes such as the SGP network [3, 4]. While the epidemiological surveillance by the SGP network selects patients with influenza-like illness (ILI) attending the general practitioner's, this surveillance study is focussed on hospitalised patients and patients at risk of severe diseases. [...]the obtained laboratory results provide information on the identification of the infection waves during an epidemic and can be implemented as a confirmation tool of the population-based surveillance.