Estimation of Excess Mortality in Germany During 2020-2022

Abstract

Background This study estimates the burden of COVID-19 on mortality in Germany. It is expected that many people have died because of the new COVID-19 virus who otherwise would not have died. Estimating the burden of the COVID-19 pandemic on mortality by the number of officially reported COVID-19-related deaths has been proven to be difficult due to several reasons. Because of this, a better approach, which has been used in many studies, is to estimate the burden of the COVID-19 pandemic by calculating the excess mortality for the pandemic years. An advantage of such an approach is that additional negative impacts of a pandemic on mortality are covered as well, such as a possible pandemic-induced strain on the healthcare system. Methods To calculate the excess mortality in Germany for the pandemic years 2020 to 2022, we compare the reported number of all-cause deaths (i.e., the number of deaths independently of underlying causes) with the number of statistically expected all-cause deaths. For this, the state-of-the-art method of actuarial science, based on population tables, life tables, and longevity trends, is used to estimate the expected number of all-cause deaths from 2020 to 2022 if there had been no pandemic. Results The results show that the observed number of deaths in 2020 was close to the expected number with respect to the empirical standard deviation; approximately 4,000 excess deaths occurred. By contrast, in 2021, the observed number of deaths was two empirical standard deviations above the expected number and even more than four times the empirical standard deviation in 2022. In total, the number of excess deaths in the year 2021 is about 34,000 and in 2022 about 66,000 deaths, yielding a cumulated 100,000 excess deaths in both years. The high excess mortality in 2021 and 2022 was mainly due to an increase in deaths in the age groups between 15 and 79 years and started to accumulate only from April 2021 onward. A similar mortality pattern was observed for stillbirths with an increase of about 9.4% in the second quarter and 19.4% in the fourth quarter of the year 2021 compared to previous years. Conclusions These findings indicate that something must have happened in spring 2021 that led to a sudden and sustained increase in mortality, although no such effects on mortality had been observed during the early COVID-19 pandemic so far. Possible influencing factors are explored in the discussion.

Keywords: causes of deaths; covid-19; excess mortality; expected mortality; mortality trends.

Figure 1. Yearly excess mortality.

The red bars show the excess mortality in 2020 (left panel), 2021 (middle panel), and 2022 (right panel) in different age groups. The gray bars are the total excess mortality.

Figure 2. The model uncertainty.

The bars show the mortality deficit and the excess mortality in 2020 (left panel), 2021 (middle panel), and 2022 (right panel) for different life tables and longevity trends.

Figure 3. The empirical standard deviation.

The blue squares show the number of all-cause deaths in Germany from 2010 to 2019, and the red squares the number of all-cause deaths in the years 2020 to 2022. The blue line shows the regression line for the years 2010 to 2019.

Figure 4. Monthly excess mortality.

For six age groups, the black lines show the monthly excess mortality from January 2020 to December 2022. The red-shaded areas show the periods where a mortality increase was observed; the green-shaded areas show the periods where a mortality deficit was observed.

Figure 5. The cumulative excess mortality.

For six age groups, the black lines show the cumulative number of excess deaths from January 2020 to December 2022. The green areas show the regions of a cumulative mortality deficit and the red areas of a cumulative excess mortality. Note that the -axis of the number of cumulative excess deaths is scaled differently depending on the age group.

Figure 6. Stillbirths in the years 2019 to 2022 in Germany.

The first panel shows the number of live births per quarter from 2019 to 2022, the second panel the number of stillbirths per quarter from 2019 to 2022, the third panel the number of stillbirths per 1,000 total births (sum of the number of stillbirths in a quarter and the number of live births in the following quarter) per quarter from 2019 to 2022, and the fourth panel the quarterly increase in the number of stillbirths per 1,000 total births in the years 2021 and 2022 compared to the mean across the years 2019 and 2020.

Figure 7. COVID-19 deaths versus excess mortality.

The blue squares show the number of reported COVID-19 deaths, the red squares the mortality deficit and the excess mortality, and the yellow squares the difference between the number of excess deaths and the number of COVID-19 from March 2020 to December 2022.

Figure 8. Number of vaccinations versus excess mortality.

Cumulative number excess of deaths (red line) and a cumulative number of fully vaccinated (blue dashed line) and triple vaccinated (green dashed line) people from March 2020 to December 2022.

Figure 9. Number of vaccinations versus excess mortality.

The red line shows the death deficit and the excess deaths, and the four dashed lines the number of vaccinations from January 2021 to December 2022.