Do current surveillance systems provide valid and credible statistical information on 2009-H1N1?
Michael A. Stoto, Ying Zhang, and Melissa A. Higdon Poster to be presented at the International Conference on Health Policy Statistics, Washington DC, January 2010 The outbreak and rapid world-wide spread of novel A (H1N1) influenza in 2009 came after almost a decade of enhancements to global disease surveillance systems. Yet even with these systems there is reason to question the validity – and the credibility – of the statistical information they provide. Although establishing a standard case definition is a critical step in an epidemiological outbreak investigation, definitions of suspected, probable, and confirmed cases varied from country to country and changed as the virus spread. Some changes reflected an evolving understanding of the epidemiology, limitations in laboratory capacity and requirements of public health practice. For some of the same reasons, case ascertainment processes varied, but typically focused on more severe cases. As a result, there was substantial uncertain
