Seasonal epidemiological and clinical characteristics of pediatric patients with respiratory syncytial virus infection by age during COVID-19: a cross-sectional study.

Abstract

Background: To date, reports have been conflicting regarding changes in the age distribution and severity of respiratory syncytial virus (RSV) hospitalizations in children since the beginning of the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to investigate the epidemiological trends and clinical characteristics of RSV infection among children hospitalized with acute lower respiratory tract infection (ALRTI) before and during the COVID-19 pandemic.

Methods: A cross-sectional study was conducted from January 2018 to December 2022 in Hunan, China. Data were collected on hospitalized children 14 years or younger with RSV-positive ALRTIs admitted to the Children's Medical Center of Hunan Provincial People's Hospital and the First Affiliated Hospital of Hunan Normal University. We evaluated their demographic characteristics, clinical features, and disease severity before and during the COVID-19 pandemic.

Results: RSV was detected in 4,255 (17.68%) of the 24,072 children, and the highest detection was 30.90% (1,248 of 4,039) in 2021. The RSV detection rates differed significantly among the years (χ²=664.741, P<0.001). Among 4,006 RSV-positive children, 62.91% were males and 98.45% were children <5 years old. We found an atypical upsurge of RSV infection in the autumn of 2020 and throughout 2021 after a major suppression in February 2020. The RSV resurge during the COVID-19 epidemic was most prominently in children aged 2-4 years. Compared with pre-pandemic, the median age of children with RSV infection during the COVID-19 pandemic increased from 8 to 12 months (Z=-12.688, P<0.001). Moreover, the proportion of children in the 1-5 months old group decreased (37.47% before vs. 23.61% during the epidemic), and the proportion of children in the 24-59 months old group increased (12.17% before vs. 24.29% during the epidemic) (χ²=92.225, P<0.001). We next compared the clinical characteristics of <5-year-old children before and during the COVID-19 pandemic by age. The wheezing ratio of each age group decreased during the COVID-19 pandemic (P<0.001), and except for the 12-23 months old group, the proportions of fever increased during the COVID-19 epidemic (P<0.001), and polypnea, dyspnea, and catarrh increased (P<0.001). In terms of disease severity, stratified by age, the proportion of children under 2 years old requiring oxygen support during the COVID-19 epidemic increased, and the proportion of invasive ventilation increased in the 6-11 months old group (2.61% vs. 0.89%, χ²=4.178, P=0.04). However, there were no differences in hospitalization duration and the proportion of children admitted to the pediatric intensive care unit (PICU) before and during the COVID-19 epidemic.

Conclusions: During the COVID-19 pandemic, RSV-infected children were older and had a lower rate of wheezing and disease severity increased in the age group of under 2 years old.