Mathias Millberg Lindholm: Pandemic mortality rates

Abstract

In the presentation we will consider a population being affected by a mortality stress during a limited period of time, for example a pandemic. During the early stages of the COVID-19 pandemic it was noted that the mortality stress during a pandemic can be viewed as a temporary shift in apparent age. We instead suggest to use a frailty based model where the baseline mortality rate is being stressed. This approach will in a natural way imply post-pandemic mortality rates at the population level. In particular, analytical results concerning the population mortality rate during and after a pandemic are derived. Under general assumptions it is shown that, compared to a non stressed scenario, the mortality is higher during the pandemic and lower after. These general results are exemplified for the Gompertz-Makeham law where more precise results can be obtained using its proportional frailty representation. The results are illustrated based on COVID-19 data for the Swedish population and we estimate the effect of the pandemic on the expected life time of an individual. These results will also be discussed in relation to a recent study of actual post pandemic mortality.
The presentation is based on joint work with Patrik Andersson, Uppsala University.