Clinical manifestations and outcomes in adults hospitalized with respiratory syncytial virus and influenza A/B: A multicenter observational cohort study

Abstract

Abstract Background Respiratory syncytial virus (RSV) and influenza cause significant health challenges, particularly for individuals with comorbidities and older adults. However, information on the clinical manifestiations and outcomes of adults hospitalized with RSV in Europe remains limited. Methods This multicenter observational cohort study of adults hospitalized with RSV or influenza A or B from March 2016 to April 2020 investigated the clinical manifestations, mortality risk factors, and association with 90-days mortality by logistic regression analysis after adjustment for covariates. Results Of 988 patients hospitalized with either virus, 353 had RSV, 347 had influenza A, and 288 had influenza B infection. Patients with RSV more often had comorbidities (83% vs. 72%, p=0.030 vs. 74%, p=0.001) and pneumonia (41% vs. 29%, p=0.028, and 24%, p<0.001) compared to influenza A and B, respectively. After adjustment for covariates, RSV infection was associated with an increased all-cause mortality within 90 days compared to influenza B infection (OR 2.16 [1.20-3.87], p=0.010) but not influenza A (OR 1.38 [0.84-2.29], p=0.207). Increasing age and present pneumonia were identified as independent risk factors of mortality in patients with RSV. Conclusion Older adults hospitalized with RSV infections are at a higher risk of dying within 90 days of hospitalization than patients admitted with influenza B, but similar to those admitted with influenza A, emphasizing the detrimental effects and severity of older patients being infected with RSV. Our findings underscore the need for strategic testing and vaccination approaches to mitigate the impact of RSV among older adults.