What Makes Scandinavia So Special?

Scandinavia, generally considered to comprise the countries of Norway, Sweden, and Denmark, contain beautiful scenery and very nice people but those are not reasons why I would want to visit them this time of the year.  After all they are all countries on Trump’s banned list.  They are all massively infected just like the rest of Europe.  However, they all have remarkably low COVID-19 death rates.  What makes them so special?
First of all let me caution that the outbreak is still early in these countries and estimating COVID-19 mortality rates is very tricky in the early phase due to exponential growth and small number statistics leading to large error uncertainties.  But it is extremely important to be able to identify early best practice countries so that others may learn from them.  For exponential growth every day that passes could have an enormous impact on final death rate.  The table below summarizes the data for these three countries and for Scandinavia as a whole.

I would say that the data is extremely intriguing but borderline statistically significant.  If we combine all three countries and analyze them as one region with larger statistics we find the coincident mortality rate is a very low 0.2% with a 95% confidence interval of 0.1% to 0.4% — consistent with common flu and way below the 3.4% estimate of the WHO.  As we noted earlier the coincident mortality rate is very likely low because the denominator overstates the actual number of cases evolving to death or recovery.  A better estimate is to assume that it takes on average 3–7 days for the disease to resolve itself from day of diagnosis.  This lagged5 rate is 1.0% with a 95% confidence range of 0.5% to 2.3% , still lower than the WHO estimate. 

If this is a real phenomenon, what might be the cause?  One possibility is that the median age in Scandinavia is about 41, substantially younger than the median age of Italy at 47.  Age might account for the difference since it is well known that age has a big impact on COVID-19 mortality.  It is also possible that the better average health of Scandinavians in terms of fewer diabetes and lower heart disease incidence also plays a strong role in keeping mortality low.  As more data is collected it might be possible to detect other differences that could help other countries manage the COVID-19 outbreak better.