Human Parainfluenza Virus Infection in Children: Hospitalization Profile in a High-Complexity Public Hospital

Human parainfluenza virus (HPIV) is an important agent of pediatric respiratory infections, ranging from mild to severe presentations such as croup and pneumonia. The presence of comorbidities may determine a higher risk of unfavorable outcomes. This study evaluated the characteristics of hospitalizations due to HPIV in a high-complexity public pediatric hospital. Retrospective study from February/2021 to May/2025, including patients under 18 years of age hospitalized for respiratory disease who underwent PCR testing for respiratory viruses using nasopharyngeal swabs. Patients were analyzed for sex, age, presence of comorbidities, clinical severity, associated viral and bacterial infections, and antimicrobial use. Clinical severity was classified as mild, moderate, or severe, depending on the need for oxygen therapy. Epi Info 7.2.6.0 was used for data analysis. Association tests were applied with calculation of odds ratios (OR), 95% confidence intervals (95%CI), and p-values. The group without comorbidities had a mean age of 13.9 ± 16.5 months (median 8.0; 0 to 97 months), and the group with comorbidities had a mean age of 48.8 ± 51.2 months (median 30.0; 1 to 220 months). Welch’s t-test = 6.92 and p < 0.0001. Regarding severity, there was no statistical difference between groups: 6/57 without comorbidities had severe disease and 13/128 with comorbidities (p = 0.5629; OR: 0.96; 95%CI: 0.35–2.67). There was also no significance in severity between serotypes 1 and 2 (n = 49) and 3 and 4 (n = 130). There was no difference regarding antibiotic use (118/185; 63.8% of patients), although a trend toward greater use in patients with comorbidities was observed (68.0% vs 54.4%), possibly related to specific clinical protocols such as in febrile neutropenia or sickle cell disease (p = 0.0546; OR: 1.77; 95%CI: 0.9385–3.3750). Viral coinfections also did not determine greater severity (p = 0.2006; OR: 1.75; 95%CI: 0.6426–4.7659). Children with comorbidities were significantly older, but without changes in the severity profile. Serotypes and coinfections were not associated with worse outcomes. Higher antibiotic prescribing may reflect specific clinical practices, but it was frequent and suggests the need for antibiotic stewardship.