Background: The causative role of respiratory viruses detected in upper airway secretions in childhood pneumonia needs further investigation.
Objective: To measure the association between infection with respiratory RNA viruses and pneumonia in children.
Methods: From March 2006 to July 2007, we conducted a case-control study of 680 pneumonia cases (WHO criteria) and 680 randomly selected, concurrently sampled age-matched controls among children aged 2–35 months in Bhaktapur, Nepal. A nasopharyngeal aspirate from each child was examined for 7 respiratory viruses using reverse transcription polymerase chain reaction. We calculated the matched odds ratios (MORs) for the detection of the individual viruses from a case compared with a control as measures of pathogenicity using conditional logistic regression.
Results: At least 1 virus was recovered in 248 (36.5%) cases and 48 (7.1%) controls. The MOR varied from 2.0 to 13.0; the highest associations were observed for parainfluenza virus type 3 (MOR 13.0; 95% confidence interval [CI] 6.0–28.0), respiratory syncytial virus (MOR 10.7; CI 4.6–24.6), and influenza A (MOR 6.3; CI 1.9–21.4). We observed that the association was lower for children age 2–5 months compared with older children for parainfluenza virus type 3 (P value for interaction 0.002).
Conclusions: All of the 7 respiratory viruses were associated with pneumonia, but their pathogenicity varied. Parainfluenza type 3, RSV, and influenza A were most strongly associated with pneumonia.
From the *Centre for International Health, University of Bergen, Bergen, Norway; †Department of Laboratory Medicine, Medical Microbiology, Sykehuset Innlandet, Lillehammer, Norway; ‡Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway; §Statens Serum Institut, Department of Epidemiology, Division of Epidemiology, Copenhagen, Denmark; ¶Child Health Department, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal; ∥Department of Microbiology, Tribhuvan University Teaching Hospital, Kathmandu, Nepal; and **Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
Accepted for publication February 18, 2010.
Supported by the European Commission (EU-INCO-DC contract number INCO-FP6–003740), the Norwegian Council of Universities' Committee for Development Research and Education (NUFU project number 2007/10177), the Research Council of Norway (RCN project number 151054 and 172226), and the Danish Council of Developmental Research (91128).
Address for correspondence: Tor A. Strand, Centre for International Health, University of Bergen, P.O. Box 7804, N-5020 Bergen, Norway. E-mail: firstname.lastname@example.org.