Full Characterization of Respiratory Syncytial Virus Pediatric Admissions Before and During the COVID-19 Pandemic: A 5-year Study

Abstract

Background: It was unknown if respiratory syncytial virus (RSV) severity changed during the COVID-19 pandemic, as previous studies presented conflicting results. It is important to understand if RSV severity is affected by viral pandemics to determine the choice of the most suitable RSV prophylactic measures. Objectives: The full characterization of the pediatric RSV hospitalized population before and during the COVID-19 pandemic, searching for changes in RSV severity. Risk factors for severe RSV disease were also analyzed. Methods: A retrospective cohort study of the RSV patients admitted to a tertiary pediatric hospital between January 2017 and March 2022. The primary outcome was the need for high-flow (HF) oxygen therapy before and during the COVID-19 pandemic. Other analyzed data included age, gender, prematurity, comorbidities, reason for admission, viral coinfections, bacterial superinfection, low-flow oxygen, non-invasive and mechanical ventilation (MV), admission to the pediatric intensive care unit (PICU), and length of stay. Results: During the COVID-19 pandemic, a slight increase in severity was observed, as the need for HF increased (P = 0.001, adjusted-P = 0.008). There was also an increase in the proportion of RSV hospitalized patients aged 24 months or older (P = 0.002, adjusted-P = 0.015). There were no differences regarding the length of stay, gender, prematurity, chronic disease, reasons for admission, bacterial superinfection, viral coinfections, admission to the PICU, low-flow oxygen therapy, non-invasive ventilation (NIV), or MV. Conclusions: Our study clarified the impact of the COVID-19 pandemic on RSV severity and found an age shift in the RSV burden during the pandemic. We concluded that RSV severity may have been affected by the COVID-19 pandemic. Since RSV severity changes with viral pandemics, it is important to continue monitoring RSV epidemiology to choose the best RSV prophylactic method, such as palivizumab or nirsevimab for infants and the RSV vaccine for pregnant women, considering the birth date of the baby, RSV seasonality, and RSV severity of that season.