Epidemiological characteristics of human parainfluenza virus infection in hospitalized children: a single-center study.

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 study analyzed the sex distribution, age-specific patterns, seasonal variations, and coinfection characteristics of HPIV infections.

RESULTS

Among the 29,260 children with ARTIs, the overall detection rate of HPIV was 5.1% (1,487/29,260). The highest positivity rates were observed in children aged <1 year (7.4%) and 1-3 years (8.1%), while the lowest was in those aged 13-18 years (1.7%; overall p < 0.001). No significant difference in detection rates was observed between male (5.3%, 845/16,056) and female patients (4.9%, 642/13,204) (p > 0.05). HPIV infections peaked in summer (9.4%), with detection rates significantly higher than in other seasons (all p < 0.001). The detection rate in 2021 (7.2%, 364/5,053) was significantly higher than in subsequent years (p < 0.001). Coinfections were detected in 28.9% (429/1,487) of HPIV-positive cases, with common co-pathogens including rhinovirus (35.2%, 151/429), Mycoplasma pneumoniae (14.5%, 62/429), and respiratory syncytial virus (13.3%, 57/429). Mixed infections were independently associated with a higher risk of severe pneumonia (adjusted odds ratio 2.45; p < 0.001).

CONCLUSION

HPIV is a significant cause of hospitalization for ARTIs in children in Shanghai, especially among those under 3 years of age, with a distinct seasonal peak in summer. Mixed HPIV infections, particularly with rhinovirus and Mycoplasma pneumoniae, are associated with more severe disease. These findings support the need for heightened clinical awareness, targeted testing during peak seasons, and consideration of mixed infection status in patient management strategies.