Burden of viral infections in an acute respiratory unit.

<bold>Introduction:</bold> High prevalence of respiratory viral infections needs new clinical epidemiologic and preventive considerations. <bold>Methods:</bold> A retrospective study was performed to estimate the prevalence of common respiratory viruses on 598 adult patients admitted to the Respiratory Diseases Clinic of Ospedale Policlinico IRCCS San Martino, Genoa for acute symptoms suggestive of a respiratory infection from Feb 2023 to Feb 2024. <bold>Results:</bold> 265(44.3%) patients (F54.3%), mean age of 72.9±14.9 did a molecular naso-pharyngeal swab. Main diagnosis were pneumonia (43.8%) and COPD exacerbation (22.6%). 74(27.9%) were positive for at least one virus, younger than negative ones (67.6±17.1 vs 75.0±13.5,p<.001).HRV 25(33.8%), H1N1 17(22.9%), HMPV 8(10.8%), RSV 7(9.5%), HPIV3 5(6.7%), and coronavirus non Sars-Cov2 5(6.7%) were the most common findings: HRV, HPIV3 and H1N1 in younger population without a seasonal trend; RSV, HMPV and other minor viruses in older patients in winter and spring. 29 (23.7%) COPD patients tested positive, more frequently among older patients (p<.001). Main reasons for hospitalization in COPD were exacerbation 59(48.4%), with HRV, H1N1 and HPIV3 virus as the most common findings, with a seasonal trend (p>.001); and pneumonia 45(36.8%) where RSV, H1N1 and HMPV were predominant. MuLBSTA score for 90-days viral pneumonia mortality, calculated for 36 patients, was low (6.81±3.07 points, i.e. 5.24% ±4.19 risk); COPD patients had a higher mean score (7.29±2.84 vs 6.50±3.23) with no significant association between COPD and viral aetiology (p=0.355). <bold>Conclusion:</bold> The high prevalence of positivity in patients admitted for airways infection emphasizes the need for careful evaluation in terms of patient isolation and infection prevention.