Background: To evaluate the efficacy of the 2009 revised dengue classification system proposed by the World Health Organization (WHO) for early detection of dengue cases requiring intervention.
Methods: Children <15 years of age with dengue [confirmed by laboratory testing (IgM enzyme-linked immunosorbent assay, NS1 Ag or reverse transcriptase polymerase chain reaction) or by epidemiologic link] who were admitted to the Institute of Tropical Medicine during the 2011 dengue outbreak in Paraguay were prospectively included. Each case was classified according to the 1997 WHO dengue criteria and by the 2009 WHO revised criteria, which categorize dengue patients using a set of clinical finding into dengue with/without warning signs and severe dengue. The management of all cases followed the new recommendations.
Results: During the 2011 dengue outbreak, 123 children were admitted with a mean age of 11 ± 3 years. By the 2009 classification system, 119 cases (97%) were classified as dengue requiring intervention [89 patients (75%) with warning signs and 30 patients (25%) with severe signs], whereas by the old system 67 patients (54%) were classified as dengue requiring intervention (P < 0.001). Further, by the 1997 classification, only 13 patients (10%) were classified as dengue hemorrhagic fever III/IV (severe cases), whereas with the 2009 classification 30 patients (24%) were considered as having severe dengue infection (P < 0.05)
Conclusions: This study confirms that the 2009 WHO dengue classification provides better detection of severe cases of dengue than the earlier 1997 WHO dengue system.