The potential health and economic value of SARS-CoV-2 vaccination alongside physical distancing in the UK: a transmission model-based future scenario analysis and economic evaluation

Abstract

Background: In response to the COVID-19 pandemic, the UK first adopted physical distancing measures in March, 2020. Vaccines against SARS-CoV-2 became available in December, 2020. We explored the health and economic value of introducing SARS-CoV-2 immunisation alongside physical distancing in the UK to gain insights about possible future scenarios in a post-vaccination era.

Methods: We used an age-structured dynamic transmission and economic model to explore different scenarios of UK mass immunisation programmes over 10 years. We compared vaccinating 75% of individuals aged 15 years or older (and annually revaccinating 50% of individuals aged 15-64 years and 75% of individuals aged 65 years or older) to no vaccination. We assumed either 50% vaccine efficacy against disease and 45-week protection (worst-case scenario) or 95% vaccine efficacy against infection and 3-year protection (best-case scenario). Natural immunity was assumed to wane within 45 weeks. We also explored the additional impact of physical distancing on vaccination by assuming either an initial lockdown followed by voluntary physical distancing, or an initial lockdown followed by increased physical distancing mandated above a certain threshold of incident daily infections. We considered benefits in terms of quality-adjusted life-years (QALYs) and costs, both to the health-care payer and the national economy. We discounted future costs and QALYs at 3·5% annually and assumed a monetary value per QALY of £20 000 and a conservative long-run cost per vaccine dose of £15. We explored and varied these parameters in sensitivity analyses. We expressed the health and economic benefits of each scenario with the net monetary value: QALYs × (monetary value per QALY) - costs.

Findings: Without the initial lockdown, vaccination, and increased physical distancing, we estimated 148·0 million (95% uncertainty interval 48·5-198·8) COVID-19 cases and 3·1 million (0·84-4·5) deaths would occur in the UK over 10 years. In the best-case scenario, vaccination minimises community transmission without future periods of increased physical distancing, whereas SARS-CoV-2 becomes endemic with biannual epidemics in the worst-case scenario. Ongoing transmission is also expected in intermediate scenarios with vaccine efficacy similar to published clinical trial data. From a health-care perspective, introducing vaccination leads to incremental net monetary values ranging from £12·0 billion to £334·7 billion in the best-case scenario and from -£1·1 billion to £56·9 billion in the worst-case scenario. Incremental net monetary values of increased physical distancing might be negative from a societal perspective if national economy losses are persistent and large.

Interpretation: Our model findings highlight the substantial health and economic value of introducing SARS-CoV-2 vaccination. Smaller outbreaks could continue even with vaccines, but population-wide implementation of increased physical distancing might no longer be justifiable. Our study provides early insights about possible future post-vaccination scenarios from an economic and epidemiological perspective.

Funding: National Institute for Health Research, European Commission, Bill & Melinda Gates Foundation.

Figure 1

Epidemiological impact of SARS-CoV-2 vaccination in the UK over 10 years Time-series of the daily number of symptomatic cases of COVID-19 in the UK for selected physical distancing scenarios and the three targeted vaccination scenarios (ages 15 years and older). Summer and winter holidays are shown in light blue and periods of increased physical distancing and initial lockdowns in light red. In vaccination scenarios, the dashed vertical line indicates the beginning of the vaccination programme. The x-axis starts on Jan 1, 2020. The y-axis is truncated at 100 000 cases daily to allow meaningful visual comparisons across panels. Not all physical distancing scenarios are shown for ease of presentation.

Figure 2

Health and economic impact of SARS-CoV-2 vaccination in the UK Results show impacts over 10 years for different physical distancing scenarios and the three vaccination scenarios. Panel A shows the estimated numbers of cases, deaths, and days of increased physical distancing; panel B shows the total costs and QALYs lost; and panel C shows the net monetary value as costs due to COVID-19 from a health-care perspective. The uncertainty in panel A reflects the values of the 95% credible interval of R₀ values used in the epidemiological model, whereas the uncertainty in panel B reflects the 95% credible interval of the Monte Carlo sampling. QALYs=quality-adjusted life-years. *Net monetary values are negative due to health losses and costs from COVID-19.

Figure 3

Value of QALYs and COVID-19 vaccine prices Sensitivity analysis on the monetary value per QALY (A) and the price per vaccinated individual, assuming two doses (B), for selected physical distancing scenarios and the three vaccination scenarios. Losses are considered from a health-care perspective. Not all physical distancing scenarios are shown for ease of presentation. QALY=quality-adjusted life-year. *Net monetary values are negative due to health losses and costs from COVID-19.

Figure 4

Wider economic impact of SARS-CoV-2 vaccination The potential wider economic impact of vaccination in terms of net monetary values for different (proportions of) daily GDP loss during different physical distancing scenarios. Uncertainty reflects the 95% credible interval of the Monte Carlo sampling. GDP=gross domestic product. *Net monetary values are negative due to health losses and costs from COVID-19.

Figure 5

Economic impact of natural and vaccine-induced protection Sensitivity analysis on the economic impact of duration of natural protection (A) and vaccine-induced protection (B) against SARS-CoV-2 infection for selected physical distancing scenarios and the three vaccination scenarios. Losses are considered from a health-care perspective. *Net monetary values are negative due to health losses and costs from COVID-19. †Vaccine-induced protection kept at 45 weeks (worst-case vaccination scenario) and 3 years (best-case vaccination scenario). ‡Natural protection kept at 45 weeks