Burden of disease methods: A guide to calculate COVID-19 Disability-Adjusted Life Years

To date, most efforts to understand the comparative population health impact of COVID-19 have been made using mortality-based metrics [1,2]. This has intensified discussion over methodological choices; in particular, how we value the life-years prematurely lost due to COVID-19 [3]. So far, the direct impact of COVID-19 on population health has varied across countries, with wide variation in incidence and infection fatality rates [4]. Understanding and quantifying the combined impact of morbidity and mortality is a key step to standardizing comparisons across countries, and to quantify the within-country impact of COVID-19 relative to other causes of disease and injury, sub-national areas or demographics [5]. This can be achieved by estimating summary measures of population health like disability-adjusted life years (DALYs). The estimation of DALYs is useful to provide comprehensive and comparative public health intelligence to inform decision-making for the management of the COVID-19 pandemic, particularly around the extent of direct and indirect consequences [6]. At present, the Global Burden of Disease (GBD) study has not integrated COVID-19. Some studies have already estimated DALYs due to COVID-19. The first published assessment was performed for Korea, up until the end of April 2020 [7]. An assessment, using a similar time frame, followed for Italy [8]. To date, published studies have only included one COVID-19 related health state, or disability weights were country-specific [7–9].