RSV-associated clinical outcomes: A decade of insight from 52 million people across Europe

<bold>Background:</bold> Respiratory syncytial virus (RSV) remains a leading cause of severe acute respiratory infection globally. Understanding the disease burden of RSV is crucial for informing preventive measures. This study investigated the outcome rates of RSV infection in hospitals and the general population. <bold>Methods:</bold> This retrospective cohort study utilised primary care and hospital data from five European countries (Estonia, France, Germany, Spain, and the UK) between 2013 and 2022, covering over 52 million individuals. We identified RSV cases using diagnostic codes and laboratory tests, and we assessed hospitalizations, intensive care unit (ICU) admissions, and mortality rates. <bold>Results:</bold> Among 44,467 patients with recorded RSV infections, the overall hospitalization rate was 35/100,000 person-years (PY). Over a decade, hospitalisation rates increased from 18 to 71/100,000PY, while ICU admission rates among hospitalised RSV patients nearly tripled from 14% to 38%. Infants aged <1 year had the highest overall hospitalisation rate (2,730/100,000 PY), followed by children aged 1–5 years (153/100,000 PY), and older adults aged ≥ 60 years (28/100,000 PY). Most hospitalizations lasted 1-2 days, with longer durations observed in infants (2-4 days) and older adults (1–5 days). The 30-day mortality rate ranged from 12 to 18/1,000 RSV patients, with the highest rate occurring in older adults and minimal to no case fatalities in children (<18 years). <bold>Conclusion:</bold> This study observed a rising trend in RSV-related hospitalizations and ICU admissions across Europe, particularly affecting infants and older adults. These findings highlight the urgent need for targeted preventive strategies for these high-risk groups.