Respiratory Syncytial Virus Infection in Children During the COVID-19 Pandemic: Findings from a Tertiary-Care Pediatric Cohort

Objective: Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in children. This study aimed to describe the clinical and laboratory characteristics of RSV-positive children older than 28 days in a tertiary-care cohort, explore characteristics associated with hospitalization in group comparisons, and identify factors independently associated with pediatric intensive care unit (PICU) admission among hospitalized children.Materials and Methods: This retrospective single-center study screened RSV testing records between August 2020 and August 2022 and included children older than 28 days with laboratory-confirmed RSV infection identified between February 2021 and August 2022. Demographic, clinical, laboratory, treatment, hospitalization, PICU admission, respiratory support, and outcome data were recorded. Comparisons were performed according to hospitalization status, clinical diagnosis, and PICU admission. A prespecified parsimonious multivariable logistic regression model evaluated factors associated with PICU admission among hospitalized children.Results: Of the 3523 children with available RSV test results during the study period, 561 RSV-positive children aged >28 days were included. Median age was 4 months (IQR, 2-14), and 317 patients (56.5%) were male. Bronchiolitis was the most common diagnosis (63.5%), followed by pneumonia (28.5%) and upper respiratory tract infection (8.0%). Hospitalization was required in 478 patients (85.2%), and 35 (6.2%) required PICU admission. Pneumonia was associated with higher rates of hypoxia, noninvasive ventilatory support, PICU admission, longer hospitalization, and delayed clinical improvement. Documented viral coinfection was detected in 30 patients (5.3%); no association was detected between documented viral coinfections and hospitalizations or PICU admission in this dataset. In hospitalized patients, pneumonia (OR, 2.59; 95% CI, 1.07-6.24; p=0.034) and hypoxia (OR, 32.08; 95% CI, 13.09-78.66; p<0.001) were independently associated with PICU admission.Conclusion: RSV infection predominantly affected infants and most commonly presented as bronchiolitis. Pneumonia and hypoxia were independently associated with PICU admission in this tertiary-care cohort.