Data insight

COVID waves: Europe and US compared by region

Driven by the South, the recent US outbreak exceeds the one in Europe

The US and Europe have gone through several waves of COVID thus far. The waves have been roughly synchronized. But their amplitudes are different. What’s more there are huge divergences once we dive into the subnational/regional dimension.

Let’s first look at weekly confirmed cases per capita. The visualization below shows the US (and its Census Bureau regions) as mirror images of continental Europe (and its regions). The values are stacked and should be read as contributions to the total case rate.

We can see that the US and European waves of COVID are synchronized – not completely, but roughly. This can be explained, in part, by common drivers. 

  • As US and Europe are both in the Northern Hemisphere, the end-of-year winter period helps fuel cases as people spend more time in indoors. 
  • Holiday schedules and school calendars show similarities – thus contributing to the spread when adults return to work and kids to school when schools reopen.  
  • The introduction of more contagious variant is also a common factor, with pandemic fatigue (which is also shared across the pond) assisting in the spread.  
  • Differences in testing also help explain things. A key reason for low case rates in both the US and Europe during the first wave was limited testing.


There are however also notable differences. Unlike the US, Europe did not have a spike in cases in July-August 2020. While the winter of 2020 was much more intense for the US, the surge in Europe started somewhat earlier (albeit from a lower base). Same goes for the most recent delta wave: more pronounced in the US, but started sooner in Europe.

It’s interesting to also look underneath the aggregate picture (see also charts at the very bottom of this post). In the US, the Northeast was driving national case rates during the first wave. During summer 2020, the South took over. During winter 2020, all regions saw major bouts. Of late, the South is again the main driver.  The consistently large contribution of the South to national case rates is remarkable (the exception being the first wave).

In Europe, the first wave was driven by all regions simultaneously, except for Eastern Europe. There was no summer wave in 2020, but soon after all regions saw a major spike led by Western Europe, followed by an even-greater spike in Northern Europe. Around April 2021, Eastern and Western Europe saw another surge, which was more muted elsewhere. The most recent delta bout has been particularly pronounced in Northern Europe.

 

How about the mortality impact? It is striking that even though the measured intensity  of cases was greater in the US, the impact on mortality turned out equally and, at some points in time, more pronounced in Europe.  Timing-wise, Europe generally led the US on the mortality impact (following the same pattern we observed on cases). The exception is the most recent wave, where differences in vaccine coverage have played a role. 

During the early stages of the pandemic, the impact on the US Northeast and everywhere in Europe (with exception of Eastern Europe) was very large. At later stages, other regions on both sides of the pond became more equally affected. Northern Europe and Eastern Europe saw a huge spike during January and April of 2021.  Finally, note how the rise in mortality in the US during the most recent wave is driven in large part by the South. 

Note: Below are two more visualizations showing developments for cases and deaths side-by-side for the US and then Europe.

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