Incidence of RSV in Adults: A Comprehensive Review of Observational Studies and Critical Gaps in Information

Background We conducted a global comprehensive literature review of observational studies reporting respiratory syncytial virus (RSV) incidence in adults and determined current evidence gaps.Methods PubMed and Embase were searched for English-language publications (2000-2022) and congress abstracts (2019-2021) reporting RSV incidence rates/cumulative incidence. Cross-sectional studies, case series, and other designs estimating only RSV frequency were excluded. The search included all geographic areas; data were extracted by age group and underlying condition where available.Results In total, 528 potentially relevant records were identified, of which 37 primary studies were relevant to this review. Most evidence was from high-income regions. Approximately two-thirds of the studies reported RSV incidence in the hospital setting. Fifteen studies included or focused exclusively on RSV incidence in adult populations with underlying conditions. Studies varied in their measurement and presentation of incidence. RSV incidence estimates were highly variable within and between geographic regions. Overall, RSV incidence tended to increase with age and was highest in adults with underlying conditions.Conclusions Estimates of RSV incidence are highly variable across populations and geographies. Further population-based studies with well-defined, consistent case definitions and surveillance strategies are needed for accurate and comparable estimates of RSV incidence, particularly in the geographic regions identified by the gap analysis. We conducted a global comprehensive literature review of studies reporting RSV incidence in adults. Estimates of RSV incidence are variable; population-based studies with well-defined case definitions and surveillance strategies are needed in addition to studies in community-based populations and lower- and middle-income regions.