Incidence of Respiratory Syncytial Virus Infection Among Patients Aged Less Than 2 Years: A Retrospective Study From an Italian Southern Region in Years 2018–2023

INTRODUCTION: Respiratory syncytial virus (RSV) is one of the most common viruses infecting nearly all children worldwide within the first 2 years of life, requiring hospitalization for over 80% of cases in infants under the age of 1. The aim of this study was to evaluate the epidemiological impact of RSV infections on hospital admissions among patients aged less than 2 years in the Abruzzo region, Italy. In addition, the analysis on patients aged less than 1 year and the evaluation of direct costs related to RSV admissions were also performed. METHODS: A retrospective observational study was performed in Abruzzo, a Southern Italian region. Data related to hospitalizations were extracted from the hospital discharge record (HDRs) of the Abruzzo region, considering all hospitalizations registered from 2018 to 2023. HDRs from patients younger than 2 years of age and diagnosed with RSV were extracted. Hospitalizations were stratified by calendar year and seasonal cycle. In addition, the analysis of costs generated by each admission was performed. RESULTS: Totally, 1899 hospitalizations for RSV (98.43 admissions/1000 inhabitants aged under 2 years of age) were recorded in the Abruzzo region during the study period. The median length of stay of all the considered hospitalizations was 5 days (IQR 5-5). The year with the highest number of hospitalizations was 2023. The incident rate among patients under 2 years of age rose from 17.42 to 19.39 in 2023 in A2 over 1000 inhabitants. About costs, the total expenditure for hospitalizations strongly increased from €579,047.29 in 2018 to €1,060,018.94 in 2023. CONCLUSIONS: This study highlights the heavy burden of RSV on hospital admissions among patients aged under 2 years in a region of Southern Italy. These results are in line with previously published research, leading to the necessity of the introduction of effective preventive measures.