# Pediatric Respiratory Infections ‎After the COVID-19 Pandemic: A Single-Center Experience

## TL;DR

This study examines the resurgence of pediatric respiratory infections, like bronchiolitis and flu, after the COVID-19 pandemic, finding that RSV caused more severe illness compared to other viruses.

## Contribution

The study provides insights into the changing patterns of viral respiratory infections in children post-pandemic and compares the clinical severity of different viruses.

## Key findings

- RSV was the most common virus (63.3%) and caused more severe symptoms and longer hospital stays.
- Children with COVID-19 had milder disease and shorter hospital stays compared to those with RSV.
- The peak of infections occurred in November, with distinct seasonal patterns observed for each virus.

## Abstract

Background

Pediatric respiratory infections, mainly bronchiolitis, are a substantial clinical burden. The most common etiology is respiratory syncytial virus (RSV). Other viruses include human rhinovirus, human metapneumovirus, influenza, adenovirus, coronavirus, and parainfluenza viruses.

Objective

We aimed to study the epidemiology and clinical characteristics of children with confirmed viral bronchiolitis and flu after the COVID-19 pandemic season and compare the behavior of each virus.

Methods

This retrospective observation study was done over seven months, from October 2022 to April 2023. All children (0-14) were included in the study if they met the clinical diagnosis of bronchiolitis or flu. Viral etiology is confirmed by PCR, using the respiratory panel available in our center which included the detection of four viruses: COVID-19, RSV, influenza A, and B. Clinical data, lab results, and X-rays were collected and correlated with each viral infection for all admitted patients.

Results

We recruited 237 children with bronchiolitis and flu symptoms from October 2022 to April 2023. The peak of infections (41%) was in November. Seasonal variations for each virus showed distinct patterns across the year. RSV peaked at the beginning of the season, gradually declining after that. In contrast, influenza A and B maintained a relatively consistent presence throughout the season. Meanwhile, COVID-19 reached its peak during March and April. One hundred forty-four (60%) of the patients were under two years of age. RSV was predominant in 150 patients (63.3%). COVID-19 was only detected in 25 patients (10%), whereas influenza A and B were equally isolated in 31 (13%) patients each. Fifty-one children (21%) were initially sick and required pediatric intensive care unit (PICU) admission, with no deaths reported. Notably, COVID-19 had a milder disease course, a shorter length of stay (LOS) in the hospital (two days) and a shorter duration of illness (five days) compared to other viruses. RSV infection was linked to more profound hypoxia and more sick children with more extended hospital stays.

Conclusion

Our study showed that, following the pandemic and the release of lockdown measures, there was another peak of upper respiratory tract infections (URTI) and flu, which was more aggressive, primarily due to other viruses, especially RSV. This resurgence was associated with more severe respiratory symptoms and an increased need for hospitalization. Notably, children with COVID-19 were in better condition compared to those with RSV.