Infectious diseases are a leading cause of morbidity and mortality worldwide with vaccines playing a critical role in preventing deaths. To better understand the impact of low vaccination rates and previous epidemics on infectious disease rates, and how these may help to understand the potential impacts of the current coronavirus disease 2019 (COVID-19) pandemic, a targeted literature review was conducted. Globally, studies suggest past suboptimal vaccine coverage has contributed to infectious disease outbreaks in vulnerable populations. Disruptions caused by the COVID-19 pandemic have contributed to a decline in vaccination uptake and a reduced incidence in several infectious diseases; however, these rates have increased following the lifting of COVID-19 restrictions with modeling studies suggesting a risk of increased morbidity and mortality from several vaccine-preventable diseases. This suggests a window of opportunity to review vaccination and infectious disease control measures before we see further disease resurgence in populations and age-groups currently unaffected.

Hospitals in England experience extremely high levels of bed occupancy in the winter. In these circumstances, vaccine-preventable hospitalisations due to seasonal respiratory infections have a high cost because of the missed opportunity to treat other patients on the waiting list. This paper estimates the number of hospitalisations that current vaccines against influenza, pneumococcal disease (PD), COVID-19, and a hypothetical Respiratory Syncytial Virus (RSV) vaccine, could prevent in the winter among older adults in England. Their costs were quantified using a conventional reference costing method and a novel opportunity costing approach considering the net monetary benefit (NMB) obtained from alternative uses of the hospital beds freed-up by vaccines. The influenza, PD and RSV vaccines could collectively prevent 72,813 bed days and save over £45 million in hospitalisation costs. The COVID-19 vaccine could prevent over 2 million bed days and save £1.3 billion. However, the value of hospital beds freed up by vaccination is likely to be 1.1–2 times larger (£48–93 million for flu, PD and RSV; £1.4–2.8 billion for COVID-19) when quantified in opportunity cost terms. Considering opportunity costs is key to ensuring maximum value is obtained from preventative budgets, as reference costing may significantly underestimate the true value of vaccines.

IntroductionHospitals 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.MethodsBased 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.ResultsIn 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.ConclusionsVaccines 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.