Non–covid-19 Respiratory Viral Infections Requiring Hospitalization: Clinical Profile, Etiologic Agents, and Antimicrobial Use in a Tertiary Hospital

Respiratory viral infections are a frequent cause of hospitalization, especially in vulnerable populations. Although the COVID-19 pandemic expanded surveillance for respiratory viruses, data on hospitalizations associated with other viruses remain limited in Brazil. Differentiating viral from bacterial etiologies is essential for rational antimicrobial use, but prescriptions often continue even after viral confirmation. This study aimed to describe the clinical and epidemiological profile of non–COVID-19 respiratory viral infections that progressed to hospitalization. Exploratory, retrospective study conducted between June 2024 and June 2025 at a tertiary, private hospital in Porto Alegre (RS). Hospitalized patients with viral infection identified by molecular tests in upper respiratory tract samples were included. Clinical-epidemiological data, viral agents, use of therapies, and outcomes were evaluated. A total of 240 respiratory viral infections were identified, and 149 cases (62.0%) not related to SARS-CoV-2 were included. There was a similar distribution between years: 77 cases in 2024 (51.7%) and 72 in 2025 (48.3%). Most patients were female (87; 58.4%), with a median age of 73 years (IQR 62–83). The most frequent virus was Influenza A (115 cases; 77.2%), followed by respiratory syncytial virus (11; 7.4%), rhinovirus (11; 7.4%), Influenza B (5; 3.4%), parainfluenza (4; 2.7%), seasonal coronaviruses not SARS-CoV-2 (4; 2.7%), and metapneumovirus (1). There was one coinfection with Influenza A and B. A specific antiviral was used in 97 patients (65.1%). Antimicrobials were prescribed in 112 cases (75.2%), despite only two having a non-respiratory infectious indication. Nineteen patients (12.8%) required ICU admission, and seven (4.7%) died within 30 days. Non–COVID-19 respiratory viral infections were a relevant cause of hospitalization in the period, with predominance of Influenza A. Despite etiological confirmation, a high rate of antimicrobial prescribing persisted, suggesting opportunities to improve care through stewardship programs. Early identification by molecular methods can support clinical decisions, rationalize therapies, and improve infection control.