COVID-19 second wave mortality in Europe and the United States

TL;DR

This paper presents new analytical methods to compare COVID-19 mortality rates across European countries and U.S. states, revealing significant heterogeneity and identifying factors associated with reductions in mortality during the second wave.

Contribution

It introduces an algorithmic approach to partition COVID-19 data into waves and learn offsets, enabling detailed comparison of mortality rate changes across regions.

Findings

Substantial heterogeneity in mortality reduction across Europe and the U.S.

The Netherlands achieved the largest reduction, up to 16 times.

Northeastern U.S. states showed the most success in reducing mortality.

Abstract

This paper introduces new methods to analyze the changing progression of COVID-19 cases to deaths in different waves of the pandemic. First, an algorithmic approach partitions each country or state's COVID-19 time series into a first wave and subsequent period. Next, offsets between case and death time series are learned for each country via a normalized inner product. Combining these with additional calculations, we can determine which countries have most substantially reduced the mortality rate of COVID-19. Finally, our paper identifies similarities in the trajectories of cases and deaths for European countries and U.S. states. Our analysis refines the popular conception that the mortality rate has greatly decreased throughout Europe during its second wave of COVID-19; instead, we demonstrate substantial heterogeneity throughout Europe and the U.S. The Netherlands exhibited the largest reduction of mortality, a factor of 16, followed by Denmark, France, Belgium, and other Western European countries, greater than both Eastern European countries and U.S. states. Some structural similarity is observed between Europe and the United States, in which Northeastern states have been the most successful in the country. Such analysis may help European countries learn from each other's experiences and differing successes to develop the best policies to combat COVID-19 as a collective unit.