Factors associated with case fatality of human H5N1 virus infections in Indonesia : a case series. Commentary

Background Indonesia has had the most human cases of highly pathogenic avian influenza A (H5N1) and one of the highest case-fatality rates worldwide. We described the factors associated with H5N1 case-fatality in Indonesia. Methods Between June, 2005, and February, 2008, there were 127 confirmed H5N1 infections. Investigation teams were deployed to investigate and manage each confirmed case; they obtained epidemiological and clinical data from case-investigation reports when possible and through interviews with patients, family members, and key individuals. Findings Of the 127 patients with confirmed H5N1 infections, 103 (81%) died. Median time to hospitalisation was 6 days (range 1-16). Of the 122 hospitalised patients for whom data were available, 121 (99%) had fever, 107 (88%) cough, and 103 (84%) dyspnoea on reaching hospital. However, for the first 2 days after onset, most had non-specific symptoms; only 31 had both fever and cough, and nine had fever and dyspnoea. Median time from onset to oseltamivir treatment was 7 days (range 0-21 days); treatment started within 2 days for one patient who survived, four (36·4%) of 11 receiving treatment within 2-4 days survived, six (37-5%) of 16 receiving treatment within 5-6 days survived, and ten (18·5%) of 44 receiving treatment at 7 days or later survived (p=0·03). Initiation of treatment within 2 days was associated with significantly lower mortality than was initiation at 5-6 days or later than 7 days (p<0 0001). Mortality was lower in clustered than unclustered cases (odds ratio 33·3, 95% CI 3·13-273). Treatment started at a median of 5 days (range 0-13 days) from onset in secondary cases in clusters compared with 8 days (range 4-16) for primary cases (p=0·04). Interpretation Development ofbetter diagnostic methods and improved case management might improve identification of patients with H5N1 influenza, which could decrease mortality by allowing for earlier treatment with oseltamivir.