Hospitals in England experience extremely high levels of bed occupancy in the winter. In these circumstances, vaccine-preventable hospitalizations due to seasonal respiratory infections, have a high cost because of the missed opportunity to treat other patients on the waiting list.

This study sought to generate evidence on the hospitalizations that vaccines for older adults against seasonal influenza (flu), pneumococcal disease (PD), respiratory syncytial virus (RSV) and COVID-19 may prevent during the winter season (October-March) in England. The monetary value of the vaccine-preventable hospitalizations was estimated using a conventional reference costing method and a novel opportunity costing approach.

Based on retrospective analysis of Hospital Episode Statistics data on hospitalizations in England, and efficacy and observed coverage rates per vaccination program, we estimated the number of bed-days that current vaccines against flu, PD and COVID-19, and a hypothetical RSV vaccine, could free up by preventing hospitalizations in the winter among older adults. We valued the freed-up bed-days (1) as the cost of prevented hospitalizations (reference cost); (2) as the Net Monetary Benefit (NMB) generated by alternative uses of the freed-up bed-days. The opportunity cost of vaccines-preventable hospitalizations is (2) when they would be an optimal use of beds or (1)+(2) when they would be a suboptimal use.

In the winter months, vaccination programs targeting flu, PD and RSV for older adults could collectively prevent 72,813 bed days and save over £45million (USD56 million) in hospitalization costs. The COVID-19 vaccine could prevent over 2 billion bed days and save GBP1.3 billion. Importantly, the value of hospital beds freed up by vaccination is likely to be 1.1–2 times larger (£48–£93 million [USD60-116 million] for flu, PD and RSV; £1.4–£2.8 billion [USD1.8-3.5 billion] for COVID-19) when quantified in opportunity cost terms. Scenario analysis replacing the current vaccine used in the adult PD program with the newly licensed pneumococcal conjugate 20-valent vaccine (PCV20), would increase the impact of each modelled outcome for this program by approximately 38 times.

Vaccines for flu, PD, RSV and COVID-19 could prevent a significant number of hospitalizations in the winter. The value of the associated freed-up bed capacity is likely to be underestimated by conventional reference costing methods.