 Retrospective data in children with dengue hemorrhagic fever DHF and dengue shock syndrome DSS, and in adults with dengue fever DF, suggested a lack of benefit from prophylactic platelet transfusion for severe thrombocytopenia in dengue patients without bleeding. However, in Taiwan and Singapore, platelet transfusion was given to 13-50 of hospitalised dengue patients. This is a prospective randomised study to examine the safety and efficacy of prophylactic platelet transfusion in adults with dengue and severe thrombocytopenia without bleeding. 