ABSTRACT
Objectives: To estimate the public health impact of COVID-19 booster vaccination in the UK during Omicron predominance, and to explore the impact in counterfactual scenarios with different booster eligibility or uptake. Method(s): A dynamic transmission model was developed to compare public health outcomes for actual and hypothetical UK Spring and Autumn 2022 booster programs. Outcomes were projected over an extended time horizon from April 2022-April 2023, assuming continued Omicron predominance as in Jan-Mar 2022. Health outcomes included averted cases, hospitalizations, long COVID cases, and deaths. NHS resource use outcomes were averted general ward and intensive care unit bed days and general practitioner visits. Patient productivity loss outcomes considered productive days lost for those in and outside the paid work force. Analyses used publicly available data. Result(s): Model output suggested that actual Spring and Autumn 2022 programs, which offered boosters to older adults and vulnerable populations, would avert approximately 716,000 hospitalizations, 1.9M long COVID cases and 125,000 deaths compared to not offering boosters in Spring and Autumn 2022. In a scenario that broadened eligibility to individuals aged >=5 years, an estimated 1.6M hospitalizations, 8.3M long COVID cases, and 222,000 deaths were averted. A scenario assuming broadened eligibility and increased uptake produced the greatest benefit among scenarios analyzed: 1.6M hospitalizations, 9.2M long COVID cases, and 228,000 deaths averted;and 953M productive days saved. Scenarios offering boosters only to high-risk individuals (aged >=5 years) were also estimated to improve benefit relative to actual programs. High-risk-only programs assuming increased uptake provided about half to two-thirds of the benefit estimated for programs assuming broadened eligibility and increased uptake. Conclusion(s): UK booster vaccination programs were estimated to provide substantial benefit to public health during Omicron predominance. Public health benefits could be maximized by broadening booster eligibility to younger age groups and increasing uptake.Copyright © 2023