Rhinovirus-associated lower respiratory tract infection in hospitalized adult patients: a retrospective cohort study

Abstract Background The role of human rhinovirus (HRV) in adult lower respiratory tract infections (LRTIs) remains controversial due to limited direct evidence of alveolar tropism and age-specific clinical characterization. Objectives To determine HRV’s clinical impact, validate its capacity to infect lower respiratory tract cells, and identify predictors for HRV-associated pneumonia in adults. Methods In this retrospective study (January 2020–December 2023), all hospitalized adults screened for HRV via RT-PCR were enrolled for analysis. In BALF HRV RNA-positive patients with available transbronchial lung biopsy (TBLB) or transbronchial cryobiopsy (TBCB) specimens, immunofluorescence (IF) staining was used to assess infection of LRT cells. Multivariable logistic regression analyzed demographics, comorbidities, and symptoms. Results HRV was detected in 4.6% (437/9,544) of patients, with bimodal seasonal peaks (February–April and September–November). Co-infection occurred in 49.0% (214/437), predominantly bacteria (34.1%) and viruses (25.7%). Among the 437 HRV-positive patients, 224 cases complicated with pneumonia, but only 34 (7.8%) met the diagnostic criteria for simple viral pneumonia. Multivariate analysis identified male (OR 2.69, 95% CI 1.04-6.99, P = 0.042), fever (OR 3.79, 95% CI 1.52–9.44, P = 0.004) and cough (OR 7.33, 95% CI 1.64–32.83, P = 0.009) as independent predictors of simple rhinovirus pneumonia. IF staining confirmed HRV VP3 protein in TBLB/TBCB specimens in 61.5% (8/13) of cases, resolving debates about HRV’s LRT cells tropism. Conclusions This study provides the first histological evidence of HRV’s LRT cells infection in immunocompetent adults. Despite high co-infection rates, HRV independently drives pneumonia, particularly in males and those with fever or cough.