Abstract
Background
The impact of SARS-CoV-2 vaccinations is often measured in terms of deaths averted, comparing to a counterfactual that assumes interactions between people in a society would have been the same without vaccines. However, many countries reduced the stringency non-pharmaceutical interventions including closures of schools and suspension of economic activity as vaccine coverage increased. Therefore, the impact of vaccines is not only in averting deaths, but also in reducing the need for socially damaging and economically costly pandemic mitigation. A counterfactual that assumes the same level of non-pharmaceutical mitigation without vaccines leads to overestimation of the number of deaths averted and underestimation of other societal costs averted by vaccines.
Methods
We define the total socio-economic cost of an epidemic and its mitigation as the sum of lost lives, lost economic activity, and lost education, which we use to identify cost-minimising mitigation in terms of business and school closures. Costs are estimated using existing monetised valuations for life years and years of education, and outcomes are simulated using an existing integrated epidemiologic-economic model named DAEDALUS. We consider the choice of mitigation to be a policy decision made to minimise total societal costs. This facilitates creation of realistic scenarios, which by comparison allow us to estimate the value of an intervention. We apply the method to the prospective assessment of the value of a one-year booster vaccination campaign in Indonesia, consisting of 187 million Moderna doses, and starting in September 2021, where the model was fit to data up to that point.
Results
The choice of cost-minimising non-pharmaceutical mitigation depends both on the availability of vaccines and on the valuation of a life year. The booster-campaign scenario results in 14 to 19 million more person–years of in-person education and an additional $153 to $204 billion in economic activity compared to the no-booster scenario in the twelve-month period. The value of the booster campaign ranges from $470 billion (95% Confidence Interval $270-$770) to $540 billion ($260-$820) in the first year, depending on life-year valuations, or $2,500 ($1,400-$4,100) to $2,800 ($1,700-$4,600) per dose. The societal benefits of booster vaccinations are substantial. Much of the value of vaccinations resides in the reduced need for costly non-pharmaceutical mitigation, suggesting that the value of vaccinations is better measured in wider socio-economic costs, rather than averted deaths.