Respiratory Syncytial Virus Co-Detection With Other Respiratory Viruses Is Not Significantly Associated With Worse Clinical Outcomes Among Children Aged <2 Years: New Vaccine Surveillance Network, 2016–2020

Abstract

Background Risk factors for severe respiratory syncytial virus (RSV) illness include early infancy, premature birth, and underlying medical conditions. However, the clinical significance of respiratory viral co-detection is unclear. We compared the clinical outcomes of young children with RSV-only detection and those with RSV viral co-detection. Methods We conducted active, population-based surveillance of children with medically attended fever or respiratory symptoms at 7 US medical centers (1 December 2016–31 March 2020). Demographic and clinical data were collected through parental interviews and chart abstractions. Nasal swabs, with or without throat swabs, were systematically tested for RSV and 6 other common respiratory virus groups. We compared clinical outcomes, including hospitalization, and among those hospitalized, length of stay, intensive care unit admission, supplemental oxygen use, and intubation, between children aged &lt;2 years with RSV-only detection and those with RSV co-detection. Results We enrolled 18 008 children aged &lt;2 years. Of 17 841 (99.1%) tested for RSV, 5099 (28.6%) were positive. RSV was singly detected in 3927 children (77.0%) and co-detected in 1172 (23.0%). RSV co-detection with parainfluenza virus or adenovirus was associated with significantly lower odds of hospitalization (adjusted odds ratio, 0.56; 95% confidence interval [CI]: .33–.95; P = .031) and supplemental oxygen use (adjusted odds ratio, 0.66; 95% CI: .46–.95; P = .026), respectively, than RSV-only detection. For all other comparisons, we did not identify a significant association between RSV co-detection and worse clinical outcomes. Conclusions Co-detection of RSV with another respiratory virus was not significantly associated with worse clinical outcomes compared with RSV-only detection.