BACKGROUND : Molecular diagnostics enable sensitive detection of respiratory viruses, but their clinical significance remains unclear in pediatric lower respiratory tract infection (LRTI). We aimed to determine whether viral coinfections increased life-threatening disease in a large cohort. METHODS : Molecular testing was performed for respiratory viruses in nasopharyngeal aspirates collected from children aged <5 years within 24 hours of hospital admission during sentinel surveillance for severe acute respiratory illness (SARI) hospitalization conducted in South Africa during February 2009–December 2013. The primary outcome was life-threatening disease, defined as mechanical ventilation, intensive care unit admission, or death. RESULTS : Of 2322 HIV-uninfected children with respiratory syncytial virus (RSV)–associated LRTI, 1330 (57.3%) had RSV monoinfection, 38 (1.6%) had life-threatening disease, 575 (24.8%) had rhinovirus, 347 (14.9%) had adenovirus (ADV), and 30 (1.3%) had influenza virus. RSV and any other viral coinfection was not associated with severe disease (odds ratio [OR], 1.4; 95% confidence interval [CI], OR, 0.74; 95% CI, .39–1.4), ADV coinfection had increased odds of life-threatening disease (adjusted OR,
3.4; 95% CI, 1.6–7.2; P = .001), and influenza coinfection had increased odds of life-threatening disease and prolonged length of stay
(adjusted OR, 2.1; 95% CI, 1.0–4.5; P = .05) compared with RSV monoinfection.
CONCLUSIONS : RSV coinfection with any respiratory virus is not associated with more severe disease when compared to RSV
alone in this study. However, increased life-threatening disease in RSV-ADV and RSV-influenza coinfection warrants further study