Respiratory viruses in nepalese children with and without pneumonia: a case-control study.

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.