Respiratory syncytial virus disease burden among adults in community and primary care settings in high-income countries: a systematic review, meta-analysis, and modelling study

Existing reports of RSV disease burden in adults focus primarily on hospitalisation while little is known about RSV disease burden in community and primary-care settings. In this study, we aimed to estimate RSV-associated acute respiratory infection (ARI) disease burden in community and primary-care settings among adults in high-income countries. We conducted a systematic literature review (PROSPERO registration: CRD42022377741) to identify published studies on RSV morbidity and mortality burden in community (including ill adults seeking or not seeking health care identified by prospective cohort studies with active case ascertainment) or primary-care settings (including outpatient and emergency department, ED) in adults in high-income countries. We accounted for the potential case under-ascertainment of RSV related to the imperfect test sensitivity of respiratory specimens and diagnostic tests by applying correction factors to the reported incidence rate and positive proportion estimates in individual studies. We estimated incidence rate and RSV positive proportion among those tested with acute respiratory illness by age group and setting. Random-effects meta-analysis was conducted to synthesise the estimates across studies. A total of six studies contributed to RSV incidence rate estimates in community or primary-care settings. The adjusted RSV incidence rate in the community was similar between persons aged 18–49 years (6104/100,000 person-years, 95% CI: 3737–9971; 1 study) and ≥ 50 years (5311/100,000 person-years, 95% CI: 3690–7643; 2 studies). In the outpatient setting, the adjusted RSV incidence rate increased with age, ranging from 2231/100,000 person-years (95% CI: 1088–4577; 2 studies) in adults aged 18–49 years to 4079/100,000 person-years (95% CI: 2759–6031; 3 studies) person-years in adults aged ≥ 65 years. Based on 1 study, RSV incidence rate in the ED was comparable between those aged 18–49 years (309/100,000, 142–676) and 50–64 years (300/100,000, 98–919), and was higher in adults aged ≥65 years (685/100,000 person-years, 95% CI: 258–2058). Based on five studies, the adjusted RSV positive proportion in adults with ARI was generally similar across the community, outpatient, and ED settings (range: 3.7–5.1%). This study revealed substantial RSV disease burden in community and primary-care settings across all age strata of adults in high-income countries. Compared to adults under age 65 years, older adults have higher RSV incidence rates in the ED and slightly higher incidence rates in the outpatient setting. These findings highlight the importance of considering RSV disease burden in community and primary-care settings when anticipating the potential impact of RSV vaccination.