Hospital Influenza Outbreak Management in the Post-COVID Era: A Narrative Review of Evolving Practices and Feasibility Considerations

Background: Hospital-acquired influenza remains a persistent threat that amplifies morbidity, mortality, length of stay, and operational strain, particularly among older and immunocompromised inpatients. The COVID-19 era reshaped control norms—normalizing N95 use during surges, ventilation improvements, and routine multiplex PCR—creating an opportunity to strengthen hospital outbreak management. Methods: We conducted a targeted narrative review of WHO/CDC/Infectious Diseases Society of America (IDSA) guidance and peer-reviewed studies (January 2015–August 2025), emphasizing adult inpatient care. This narrative review synthesizes recent evidence and discusses theoretical implications for practice, rather than establishing formal guidelines. Evidence was synthesized into pragmatic practice statements on detection, diagnostics, isolation/cohorting, antivirals, chemoprophylaxis, vaccination, surveillance, and communication. Results: Early recognition and test-based confirmation are pivotal. For inpatients, nucleic-acid amplification tests are preferred; negative antigen tests warrant PCR confirmation, and lower-respiratory specimens improve yield in severe disease. A practical outbreak threshold is ≥2 epidemiologically linked, laboratory-confirmed cases within 72 h on the same ward. Effective control may require immediate isolation or cohorting with dedicated staff, strict droplet/respiratory protection, and daily active surveillance. Early oseltamivir (≤48 h from onset or on admission) reduces mortality and length of stay; short-course post-exposure prophylaxis for exposed patients or staff lowers secondary attack rates. Integrated vaccination efforts for healthcare personnel and high-risk patients reinforce workforce resilience and reduce transmission. Conclusions: A standardized, clinician-led bundle—early molecular testing, do-not-delay antivirals, decisive cohorting and Personal protective equipment (PPE), targeted chemoprophylaxis, vaccination, and disciplined communication— could help curb transmission, protect vulnerable patients and staff, and preserve capacity. Hospitals should codify COVID-era layered controls for seasonal influenza and rehearse unit-level outbreak playbooks to accelerate response and recovery. These recommendations target clinicians and infection-prevention leaders in acute-care hospitals.