OBJECTIVES: RSV causes acute respiratory disease (ARD), including severe lower respiratory tract disease (LRTD), which can result in hospitalization and death. The study objective was to compare the potential benefit of a hypothetical RSV vaccination strategy in US versus UK older adults.

METHODS: A decision-analytic model was developed using local data on the incidence of RSV, proportion of RSV cases that are LRTD, healthcare resource utilization rates, and RSV-related mortality in adults ≥60 years. UK estimates included hospital- and community-associated RSV deaths, whereas US estimates were based on hospital-related deaths only. To compare across countries, the number needed to vaccinate (NNV) was estimated as the reciprocal of the absolute value of the difference of the event rate in the vaccinated and unvaccinated cohorts.

RESULTS: For 1 million individuals, the estimated annual number of LRTD hospitalizations were lower in the UK (1252) compared with the US (1665) without an RSV vaccine. If an RSV vaccine with an efficacy of 75% against ARD, LRTD, and LRTD hospitalizations was used, the NNV to prevent one hospitalization would be 1315 in the UK and 1180 in the US. Without an RSV vaccine, the RSV-attributable deaths in the UK were higher than those in the US (682 versus 126). The NNV to prevent one death is lower in the UK (2415) versus the US (15,574).

CONCLUSIONS: Results suggest there are higher rates of RSV-attributable deaths in the UK despite a lower hospitalization rate; this is likely because the UK data include hospital- and community-associated deaths. To characterize the full burden of severe RSV disease in the US, mortality data outside of the hospital is needed. Despite limitations on US mortality data and differences in healthcare systems, in both countries, an effective RSV vaccine appears to prevent significant morbidity and mortality in older adults.