Afebrile Presentation in COPD Patients with Influenza A: A Risk Factor for Prolonged Viral Shedding

To investigate the risk factors for prolonged viral shedding in influenza A patients treated with oseltamivir and analyze fever patterns in chronic obstructive pulmonary disease (COPD) patients.

This retrospective study analyzed 309 hospitalized patients with RT-PCR-confirmed influenza A at a multi-campus tertiary medical center from 2022 to 2025. Influenza A virus retesting was performed on day 6 of antiviral treatment to assess viral clearance. Multivariate logistic regression was used to identify risk factors for prolonged viral shedding. ROC curve analysis evaluated the predictive value of absolute lymphocyte count (ALC). Subgroup analyses compared fever patterns in COPD and non-COPD patients using the Mann-Whitney U and chi-square (χ²) tests.

Overall, 309 influenza A inpatients were included. Six independent risk factors for prolonged viral shedding were identified: older age (95% CI 1.01-1.05), lymphopenia (95% CI 0.09-0.38), cerebrovascular disorders (95% CI 1.64-16.08), immunosuppressants (95% CI 1.05-3.36), delayed antiviral treatment (95% CI 4.13-15.27), and fungal coinfection (95% CI 1.25-4.69). Notably, 63.7% of the COPD patients were afebrile, compared to 23.6% of non-COPD patients (p < 0.05). In the COPD group, prolonged shedders had higher odds of afebrile status (95% CI 1.39-12.59), lower ALC (95% CI 0.01-0.17) and delayed oseltamivir initiation (95% CI 1.65-13.28) than nonprolonged shedders. The ALC demonstrated good predictive accuracy for prolonged viral shedding (AUC 0.75 overall; AUC 0.77 for the COPD group).

Early antiviral therapy and targeted management for high-risk groups (especially COPD patients) are valuable. Afebrile presentations in COPD patients highlight the importance of routine influenza testing during exacerbations.