# Pathogen trends and paradigm shifts of respiratory infections in children: a 5-year retrospective study from Perugia

## TL;DR

This study compares respiratory infections in children before and after the COVID-19 pandemic in Perugia, showing changes in pathogens and hospitalization trends.

## Contribution

The study provides a 5-year comparison of respiratory infection trends in children, highlighting post-pandemic shifts and the impact of molecular testing.

## Key findings

- Respiratory infections remained the most common cause of pediatric hospitalizations in the post-COVID-19 era.
- Molecular testing led to shorter hospital stays and fewer antibiotic prescriptions.
- Respiratory Syncytial Virus and Influenza showed earlier and more severe peaks after the pandemic.

## Abstract

Respiratory infections are one of the most common causes of morbidity and mortality among children. After the COVID-19 pandemic, the epidemiology of respiratory tract infections has changed and has been better traced by more frequent and less expensive molecular and antigenic tests. The main aim of this retrospective study was to evaluate the epidemiology of respiratory infections among children hospitalized in Perugia during the epidemic seasons of 2018–2019 and 2023–2024, comparing clinical severity, hospitalization length, diagnostic and therapeutic interventions.

We retrospectively analysed hospital records of all patients admitted to our clinic from October 2018 to March 2019 and from October 2023 to March 2024.

In the post-COVID-19 era, hospitalizations for respiratory infections increased proportionally to other hospitalization causes, remaining the most common ones. Length of hospital stay was shorter, with no difference based on age, C-Reactive Protein levels or symptoms at admission. A change of respiratory infection epidemiology after the COVID-19 pandemic has been witnessed also in our setting: Respiratory Syncytial Virus and Influenza played a central role, displaying earlier peaks and severe clinical pictures. Increased use of molecular testing allowed for prompt etiological diagnoses, likely contributing to shorter inpatient stays and fewer antibiotic prescriptions, thus reducing economic burden for each patient and promoting improved antibiotic stewardship.

In our setting, respiratory infections still accounted for the majority of pediatric hospitalizations during the autumn/winter seasons. A comprehensive testing strategy for etiological diagnosis of respiratory infections in hospitalized patients seemed to be cost-effective by reducing hospital stay and antibiotic prescriptions. This study may inform healthcare policy by emphasizing the importance of etiological diagnosis and the economic burden of inappropriate treatments.

The online version contains supplementary material available at 10.1186/s13052-025-02183-5.