The Max Planck Institute has updated their Human Mortality Database with one more week's worth of data, so I decided to re-look at my theory that prior flu season severity might impact Covid deaths.
mortality.org
mortality.org
Looking at the USA, I noticed that both 2019 and 2020 had very low excess mortality relative to prior years: 
To normalize seasonality, I created a trailing 52 week moving average, which clearly shows the "missing" fatalities and the Covid "catch-up" effect. For the USA, Covid has mainly acted to return mortality to trend:
Looking at European nations with large excess mortality shows that this is a consistent pattern. Here is Spain, for instance:
Here is England and Wales:
Here is Scotland:
Here is the Netherlands:
Here is Sweden:
Here is Italy:
Finally, here is France:
The pattern isn't perfectly replicated everywhere, but there is definitely a consistency with deaths falling below the recent trend and then catching up very suddenly. But, maybe non-impacted countries also had mild flu seasons?
So, I build the same graphs for all the other countries for which data was available. Here is Finland, for instance:
The effect in Finland is similar but very muted. How about Germany?
Or Estonia?
Hungary?
Iceland:
Israel:
Luxembourg:
Lithiuania:
Norway:
Portugal:
Slovakia:
Other than perhaps Iceland, the other countries in Europe did not display the same two year pattern as the badly hit countries. Interestingly, Italy appears to have had three consecutive relatively mild seasons, not being as badly impacted in 2018 as some other nations.
