Background: Most deaths from pneumonia in children <5 years of age occur in developing countries, where information about the clinical impact and severity of viral causes of respiratory infections is limited.
Methods: From June 29, 2004 to June 30, 2007 we evaluated 2230 cases of pneumonia (World Health Organization criteria) in children aged 2 to 35 months in Bhaktapur, Nepal. A nasopharyngeal aspirate from each case was examined for 7 respiratory viruses using reverse-transcription polymerase chain reaction. We compared illness duration, severity, and treatment failure between cases positive and negative for the individual viruses in multiple regression models.
Results: A total of 2219 cases had a valid polymerase chain reaction result and were included in the analyses. Overall, 46.1% of cases were 2 to 11 months of age. Being infected with respiratory syncytial virus (RSV) was associated with lower chest indrawing (odds ratio [OR] 2.17; 95% confidence interval [CI] 1.42–3.30) and, among infants, oxygen saturation <93% (OR: 1.88; CI: 1.32–2.69). Among the 2088 nonsevere pneumonia cases, those positive for RSV had a longer time to recovery (hazard ratio 0.82; CI 0.75–0.90; P < 0.001) and an increased risk of treatment failure (OR: 1.75; CI: 1.34–2.28; P < 0.001) than the RSV negative cases.
Conclusions: Being infected with RSV was associated with a more severe clinical presentation of pneumonia, longer illness duration, and increased risk of treatment failure. The severity of RSV infection was age related, infants being more severely affected.