Safety and Efficacy of Therapeutic Agents in Viral Pneumonia in Immunosuppressed Patients
Canan Akman, Busra Erdem, Asli Bahar Ucar, Ozlem Inci, Mehmet Unaldi, Bilgen Ozkaya, Gokhan Yilmaz, Ozgur KarciogluIntroduction/Objective:
Immunosuppressed Patients (ISP) — defined by congenital or acquired deficiencies in systemic defense mechanisms — are disproportionately susceptible to viral respiratory infections. Agents such as SARS-CoV-2, Respiratory Syncytial Virus (RSV), influenza A and B, and Cytomegalovirus (CMV) cause significant morbidity in both immunocompetent and immunosuppressed individuals. Clinical manifestations range from mild influenza-like illness to severe pneumonia, respiratory failure, multiorgan dysfunction, and concurrent bacterial infections.
Methods:
A narrative synthesis of the literature was performed using Medline, CINAHL, Web of Science, and Scopus using relevant keywords ("immunosuppressed patients", "pneumonia", "lung infection", "antiviral", "cytomegalovirus", "influenza", "RSV") for publications between January 2000 and March 2026. Where available, Cochrane systematic reviews, meta-analyses, and high-quality randomised controlled trials were given precedence in the narrative synthesis; systematic review and meta-analytic procedures, including PRISMA guidelines, were not applied. Case reports, editorials, and opinion articles were excluded, other than a small number of case series describing rare therapeutic strategies for which no higher-level evidence was available. Evidence was collated narratively and presented in tabular format.
Results:
Although numerous antiviral compounds have been developed and studied, the optimal agent for managing severe viral infections in ISP remains uncertain. Empiric oseltamivir for influenza is typically initiated immediately upon clinical suspicion. Other antivirals — including ganciclovir for CMV, cidofovir for adenovirus, and ribavirin for RSV or parainfluenza — are generally reserved for confirmed or highly suspected infections in high-risk populations. The safety profile of each agent must be evaluated individually before initiating the treatment.
Discussion:
Direct-acting antivirals achieve faster virologic clearance but do not consistently reduce shortterm mortality in ISP. Antiviral selection requires integration of pathogen identity, timing of therapy, underlying immune deficit, and individual risk-benefit assessment. Novel agents and combination strategies warrant further investigation in this population.
Conclusion:
ISP with viral pneumonia represents a clinically complex, high-risk group requiring individualized treatment strategies, including antiviral agents, vigilant safety monitoring, and proactive preventive measures, especially vaccination. Virologic clearance benefits associated with direct-acting antivirals such as remdesivir do not consistently translate into a short-term mortality benefit, underscoring the need for outcome- specific interpretation of the evidence. A nuanced understanding of the available antiviral armamentarium is essential to optimise outcomes in this vulnerable population.