Introduction: Respiratory syncytial virus (RSV) can cause severe outcomes among adults. However, RSV incidence in adults is frequently underestimated due to non-specific symptomatology, limited standard-of-care testing, and lower test sensitivity compared to infants. We conducted a retrospective observational study to estimate RSV-attributable incidence of hospitalizations among adults in Germany between 2015 and 2019. Methods: Information on hospitalizations and the number of people at risk of hospitalization (denominator) was gathered from a Statutory Health Insurance (SHI) database. A quasi-Poisson regression model accounting for periodic and aperiodic time trends and virus activity was fitted to estimate the RSV-attributable incidence rate (IR) of four specific cardiovascular hospitalizations (arrhythmia, ischemic heart diseases, chronic heart failure exacerbations, cerebrovascular diseases) and four specific respiratory hospitalizations (influenza/pneumonia, bronchitis/bronchiolitis, chronic lower respiratory tract diseases, upper respiratory tract diseases). Results: RSV-attributable IRs of hospitalizations were generally increasing with age. Among cardiovascular hospitalizations in adults aged ≥60 years, arrhythmia and ischemic heart diseases accounted for the highest incidence of RSV-attributable events, followed by chronic heart failure exacerbation, with annual IR ranges of 157-260, 133-214, and 105-169 per 100,000 person-years, respectively. The most frequent RSV-attributable respiratory hospitalizations in adults aged ≥60 years were for chronic lower respiratory tract diseases and bronchitis/bronchiolitis, with annual IR ranges of 103-168 and 77-122 per 100,000 person-years, respectively. Conclusion: RSV causes a considerable burden of respiratory and cardiovascular hospitalizations in adults in Germany, similar to other respiratory viruses (e.g., influenza and SARS-CoV-2). This highlights the need to implement effective prevention strategies, especially for older adults.

Aleksandra Polkowska-Kramek, Robin Bruyndonckx, Worku Biyadgie Ewnetu, Pimnara Peerawaranun, Maribel Casas, Thao Mai Phuong Tran are employees of P95 Epidemiology & Pharmacovigilance, which received funding from Pfizer to conduct the research described in this manuscript and for manuscript development. Caihua Liang, Caroline Lade, Lea Johanna Bayer, Bennet Huebbe, Gordon Brestrich, Christof von Eiff, Bradford D. Gessner, and Elizabeth Begier are Pfizer employees and may own Pfizer stock. Gernot Rohde is an expert in the field of RSV and received an honorarium from Pfizer for input on the study design.

This study was funded by Pfizer Ltd.

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The datasets generated and/or analyzed during this study are not publicly available (data provider's restrictions). Weekly counts of hospitalized cases and extrapolation factors were provided by the Gesundheitsforen Leipzig GmbH.