add DALYs to record of infections
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Disability-adjusted life years (DALYs) are a measure of both the fatal and non-fatal health burden caused by a condition in a population. DALYs are composed of years of life lost (YLL) and the years living with disability (YLD).
The fatal health burden caused by a condition can be quantified through YLL. All we would need to calculate an estimate for the YLL caused by COVID in a population is to find the average life-expectancy in a population, and keep a record of the person's age at the time of death, the YLL are then calculated by the average life expectancy of this person minus their age at the time of death. The is repeated for all persons to find the YLL of a condition in a population.
Example: Person 1 died at 20, person 2 died at 60, life expectancy is 90
Person 1 YLL = 90 - 20 = 70, Person 2 YLL = 90 - 60 = 30. Populations YLL are the sum of each individuals YLL.
The non-fatal health burden caused by a condition can be quantified through YLD. To calculate this, we first need to find DALY weights for COVID, which are a number between 0 and 1 which quantifies how much harm a condition causes this person, for a disease like COVID with varying severity each level (asymptomatic, moderate, severe etc..) we would need to find DALY weights for each level. Data for this is available, e.g. https://www.ssph-journal.org/articles/10.3389/ijph.2022.1604699/full. We then work out how long each person had each level of COVID severity.
Example: Person 1 had mild COVID for a week and recovered, Person 2 had mild COVID for a week and severe COVID for a week (DALY weights are taken from above link).
Person 1 YLD = 7 / 365 * 0.051 = 0.0009808, Person 2 YLD = 7 / 365 * 0.051 + 7 / 365 * 0.133 = 0.00353148, Populations YLD are the sum of each individuals YLD.
DALYs are calculated with the following equation:
DALYS = YLD + YLL
More info on DALYs: