Results: The applicability of the DF/DHF/DSS classification was limited, even when strict DHF criteria were not
applied (13.7% of dengue cases could not be classified using the DF/DHF/DSS classification by experienced
reviewers, compared to only 1.6% with the revised classification). The fact that some severe dengue cases could not
be classified in the DF/DHF/DSS system was of particular concern. Both acceptance and perceived user-friendliness of
the revised system were high, particularly in relation to triage and case management. The applicability of the revised
classification to retrospective data sets (of importance for dengue surveillance) was also favourable. However, the
need for training, dissemination and further research on the warning signs was highlighted.