Objective This study aims to investigate the epidemiological characteristics of human parainfluenza virus (HPIV) infections in hospitalized children with acute respiratory tract infections (ARTIs) at a single center in Shanghai, and to provide scientific evidence for optimizing diagnostic and therapeutic strategies for pediatric ARTIs. Methods A retrospective study was conducted on 29,260 children hospitalized with ARTIs at Shanghai Children’s Hospital between January 2021 and December 2024. The