Prevalence rate and clinical risk factors for adverse outcomes of lower respiratory tract infection in children under 5

The aim is to systematize clinical studies to identify the most significant predictors of adverse outcomes in acute lower respiratory tract infections in children caused by common pathogens. Analytical review of scientific literature is carried out in PubMed, Global Health and RINC databases examining the past 10 years (2014–2024). The analysis considers cohort studies, systematic reviews, and meta-analyses, as well as clinical reports. Adverse outcomes include: the need for oxygen therapy, mechanical ventilation, hospitalization with a stay in intensive care units, long-term inpatient treatment (over 5 days) and mortality. Key findings: 1. The underlying conditions that predispose to a complicated course of respiratory syncytial virus infection, Influenza, metapneumovirus and COVID-19 have been established. These conditions include chronic comorbidities (bronchopulmonary dysplasia, cardiovascular and neurological disorders, nutritional deficiencies, anaemia); congenital malformations of the heart; prematurity; Down syndrome; being under 1 year of age, as well as mucoviscidosis, vitamin D deficiency as significant risk factors for children under 5 years with severe respiratory syncytial virus infection. 2. Analysis by age group reveals high-risk groups, particularly vulnerable to the development of severe infections. This highlights the need for priority prevention (including vaccination against respiratory syncytial virus infection and influenza) and early diagnosis to minimise negative outcomes. The analysis highlights the importance of a comprehensive approach to prevent serious complications in acute respiratory infections in children.