COVID-19, Influenza, and RSV in Children and Adults: A Clinical Comparative Study of 12,000 Cases.

(1) Background: Respiratory virus infections, including Coronavirus disease 2019 (COVID-19), seasonal influenza (FLU), and respiratory syncytial virus (RSV) as prominent examples, can severely affect both children and adults. This study aimed to investigate the clinical characteristics of respiratory viral infections in pediatric and adult populations and to identify determinants influencing patient hospitalization. (2) Methods: This retrospective study analyzed the electronic medical records of patients admitted to a regional hospital's emergency department from 1 January 2015 to 31 December 2022, to investigate the clinical characteristics and hospitalization risk factors associated with these three viruses. (3) Results: Infants aged 1 to 11 months were most affected by COVID-19 and RSV, whereas FLU more commonly infected children aged 3 to 5 years. Key factors influencing hospitalization included age and abnormal chest X-ray findings, with higher risks observed in younger children and adults over 65. Notably, the presence of abnormal chest x-ray findings significantly increased the hospitalization risk by 1.9 times [1.5-2.4] in children and 21.4 times [2.4-189.0] in adults. (4) Conclusions: This analysis underscores the impact of COVID-19, FLU, and RSV on hospitalization risk, offering insights for managing these respiratory viral infections (RVIs). Age-related risk differences highlight the necessity for tailored strategies, improving understanding of and treatment development for RVIs.