Of the 383 cases reported between November 2003 and May 2008 from these 15 countries, 10 .4% involved patients aged\9 years, 24% involved patients between ages 10 and 19 years, and 25% involved patients aged 20-29 years [4] . The overall CFR of H5N1 infection was 65%, and the CFR for patients aged 10-19 years was 78%, which was highest among all age groups [4] . Patients for whom the disease was ultimately fatal showed respiratory failure and progressed to pediatric acute respiratory distress syndrome (ARDS), which in patients infected with H5N1 influenza virus consisted of severe viral pneumonia accompanied by diffuse alveolar damage that was induced by intense cytokine reactions and inflammation [5] . Wiwanitkit investigated hematologic findings among reported H5N1infected patients and observed lymphopenia and anemia, but he did mentioned that the effects of the infection on platelet count were controversial [6] . A knowledge of the clinical factors present at admission to the hospital that are associated with prognosis may be useful when the aim is timely and adequate consultation and treatment. As many of the studies on the H5N1 virus have each only reported a few cases of H5N1 influenza, it has been difficult to get identify these clinical factors adjusted with other confounding factors, such as age and sex. Here, we report our investigation of the early indicators of prognosis in patients with H5N1 influenza aged \18 years which we identified from a pooled analysis of case reports.