Cost-effectiveness of routine COVID-19 adult vaccination programmes in England

In England, and many other countries, immunity to SARS-CoV-2 infection and COVID-19 disease is highly heterogeneous. Immunity has been acquired through natural infection, primary and booster vaccination, while protection has been lost through waning immunity and viral mutation. During the height of the pandemic in England, the main aim was to rapidly protect the population and large supplies of vaccine were pre-purchased, eliminating the need for cost-effective calculations. As we move to an era where for the majority of the population SARS-CoV-2 infections cause relatively mild disease, and vaccine stocks need to be re-purchased, it is important we consider the cost-effectiveness and economic value of COVID-19 vaccination programmes. Here using data from 2023 and 2024 in England on COVID-19 hospital admissions, ICU admissions and deaths, coupled with bespoke health economic costs, we consider the willingness to pay threshold for COVID-19 vaccines in different age and risk groups. Willingness to pay thresholds vary from less than £1 for younger age-groups with- out any risk factors, to over £100 for older age-groups with comorbidities that place them at risk. This extreme non-linear dependence on age, means that despite the different method of estimating vaccine effectiveness, there is considerable qualitative agreement on the willingness to pay threshold, and therefore which ages it is cost-effective to vaccinate. The historic offer of COVID-19 vaccination to those 65 and over for the autumn 2023 programme and those over 75 for the spring 2023 programme, aligns with our cost- effective threshold for pre-purchased vaccine when the only cost was administration. However, for future programmes, when vaccine costs are included, the age-thresholds slowly increase thereby demonstrating the continued importance of protecting the eldest and most vulnerable in the population. Graphical Abstract Research In Context Evidence before this study We searched PubMed, Google Scholar, and medRxiv for articles published in English from inception to Nov 19, 2024, with the following search terms: “COVID-19” AND “vaccin*” AND “cost-effective*”. A total of 1287 articles were identified, of which 47 considered the cost-effectiveness of vaccination against COVID-19; of these only 12 considered booster vaccination against Omicron, and only 6 considered regular vaccination. These studies focused on USA (× 2), South Korea, Thailand, Germany and the UK. Added value of this study This study provides the first independent assessment of the cost-effectiveness of the spring and autumn COVID-19 vaccination programme in the UK, and the first to consider vaccination across the spectrum of ages. It uses UK data from the Spring and Autumn boosters 2023 on severe health outcomes (hospital admission and deaths) partitioned by age, risk group and vaccine status to estimate the impact of immunisation programmes. This is combined with health economic estimates to determine the willingness-to-pay for the costs of immunisation (vaccine plus administration costs) in each age and risk group. Implications of all the available evidence Which ages and risk groups it is cost-effective to vaccinate depends on the price paid for the vaccine, although the increase in risk of severe illness with age dominates the results. Vaccination of individuals under 65 years old without additional risk factors is unlikely to be cost-effective at any vaccine price. However, universal vaccination (in both Spring and Autumn for all risk groups) for older adults is likely to be cost-effective if the vaccine can be secured for a sufficiently low price.