Clinical Burden of Disease and Demographics in Older Adults Hospitalized with RSV Infection in England: A Retrospective Cohort Study

Respiratory syncytial virus (RSV) causes significant disease in older and comorbid adults. Current UK vaccination recommendations restrict eligibility to adults ≥ 75 years, 65–74 years with chronic respiratory disease or immunosuppression, and those in care homes, but evidence on clinical burden in adults < 75 years with comorbidities is limited. This study assessed patient characteristics, healthcare resource utilization (HCRU), and mortality in adults hospitalized with RSV in England. Population-based retrospective cohort study using linked Clinical Practice Research Datalink Aurum and Hospital Episode Statistics. Adults ≥ 60 years hospitalized with RSV between October 2014 and March 2019 were included. We defined RSV episodes as 90 days post-diagnosis. We defined cases using diagnosis codes for confirmed RSV (RSV-specific) or acute lower respiratory tract infection with exclusion of other causative pathogens (RSV-possible). All-cause HCRU (hospitalizations, critical care admissions, outpatient attendance, primary care consultations, and prescriptions) and case fatality rates were assessed. Results were stratified by age (60–74 and ≥ 75 years), case definitions (RSV-specific, RSV-possible), and comorbidity profiles (chronic respiratory disease, immunocompromised, cardiovascular disease). A total of 97,712 hospitalized episodes in those aged ≥ 60 years were included in the analysis, of which 785 (0.8%) were RSV-specific cases ( n = 338 aged 60–74 years, n = 447 aged ≥ 75 years). In RSV-specific cases, median (IQR) cumulative length of stay (LoS) for those ≥ 75 years was 10.00 (6.00–22.00) days, which was equivalent to or lower than each comorbidity subgroup in those aged 60–74 years, with the longest LoS in those immunocompromised (11.50 [7.00–26.00] days). Critical care admissions were more often observed across comorbidity stratifications (13.85–22.34%) compared to those ≥ 75 years (5.03%). All-cause and RSV-related case fatality rates for RSV-specific cases were highest among those ≥ 75 years (all-cause: 19.3%; RSV-related: 10.3%). HCRU within RSV episodes in those aged 60–74 years across comorbidity profiles was equal to or greater than that in those aged ≥ 75 years. These findings highlight the need to prioritize consideration of comorbidity groups that could benefit from RSV vaccination.