Changing socioeconomic inequalities in the incidence and case fatality rates of COVID-19 in Germany, March 2020 through May 2022: an ecological study.

Background: Socioeconomic disparities in COVID-19 burden were widely observed during the pandemic's early waves, including in Germany, but studies on whether these inequalities have persisted or changed as the pandemic progressed are lacking.

Methods: We used an ecological study design to assess the relationship between a range of demographic, socioeconomic, and healthcare-related predictors and COVID-19 impact in Germany. Specifically, we fit generalized additive models to cumulative, district-level (n = 400) COVID-19 incidence and case fatality rates (CFRs) for each of the first five pandemic waves, which covered the period from March 2020 through May 2022.

Results: We find that associations between socioeconomic deprivation and COVID-19 impact evolved over time. Specifically, districts with higher levels of deprivation experienced lower incidence initially, but higher incidence beginning in the second half of wave 1 and persisting through wave 3. Meanwhile, more deprived districts experienced higher CFRs initially as well as during waves 3 through 5, but lower CFRs during the second half of wave 1. Finally, during the first four waves, we find that district-level CFRs scaled superlinearly with incidence, suggesting that the risk of death increased with incidence. This relationship was particularly strong during the first pandemic wave.

Conclusions: The association between socioeconomic position and COVID-19 impact in Germany has been complex, with patterns changing in intensity and direction over time. Continued monitoring of socioeconomic inequalities in COVID-19 impact, in particular at the individual level, is needed to better understand if and how inequalities continue to persist. Such monitoring will be instrumental in informing more equitable control strategies.