South Korea defies pandemic records

Philip Schellekens  |  
Cases in South Korea have risen at a pace previously unseen among peers

South Korea is among the several countries in the East Asia & Pacific region that have recently experienced a very rapid escalation in the growth of COVID-19 cases.  This occurred in the face of more transmissible variants and following relative success in suppressing earlier variants (as this companion post discusses). But the scale of the surge has been in its own league.


South Korea compared to UK and US

To start off, let us make a comparison on case rates between South Korea, the UK and US. The first chart below tracks daily 7-day trailing averages of cases per capita. It clearly shows that South Korea’ s successive waves are well above anything the UK or the US have experienced so far. This also comes through in the cumulative case numbers (second chart).  In merely a month or two have cumulative rates caught up to what took the UK and US two years to accumulate. And cases continued to rise considerably in recent months. 

Next, let us repeat the above comparisons for mortality rates. While Omicron doe snot have the lethality properties of Delta, we note that given its high transmissibility all countries suffered a considerable rise in mortality rates. But what a striking difference again between South Korea and the US and UK. South Korea did manage to avoid a major spike in mortality and also cumulative mortality remained at merely a fraction of the UK and US numbers, even though – as the earlier charts showed – cumulative case rates are higher. 

South Korea compared to the rest of the world

So far we have compared South Korea with that of the UK and the US. But how does the country compare more broadly with other countries in the world? How unparalleled is its experience really? In what follows we will show a number of comparison charts that start off with the broadest comparison possible and then narrows this down to more relevant peer groups. 

The first chart below compares South Korea with ALL countries of the world (click on the chart for a higher-resolution version). The red line traces South Korea and the blue lines map the trajectories of the other 195 countries in our universe of countries.

The recent spike on the cases side is clearly unprecedented even though its height has been replicated in recent (Omicron) history in a few other countries. On the mortality side, South Korea is again on the high side, even though this is far from unique even as we consider the more recent period in which countries were affected by Omicron.

South Korea has a population of 52 million people. So it is fair to make a comparison that controls for absolute population size. We can think of two reasons why that is important:

  • Smaller countries tend to be more dense, especially on the lower end of the population size spectrum, and density tends to facilitate spread and thereby raise infection prevalence, keeping all else equal. 
  • Viruses spread from person to person; they’re not infecting everyone uniformly at the same time. Geography therefore matters. Compare for example China with Hubei and Hubei with Wuhan at the height of their crises early 2020. As we progress to geographically smaller units, the per capita numbers tend to be higher when outbreaks are concentrated.

In the above chart, we compare South Korea with other large countries in the world. We set the cut-off at 20 million people, which leaves us with a total of 60 countries exceeding the cut-off. As we can see, the country is a total outlier when it comes to cases. It is also an outlier when it comes to mortality at the current time, but not from a historical perspective.

Next, we narrow the sample further to large countries that fall in the group of high-income countries. The income classification of the World Bank helps examine the differential impacts of COVID as countries exhibit different vulnerabilities depending on whether they are rich or poor. They also demonstrate different capabilities in correctly measuring the impacts. For this reason, let’s compare South Korea with its peer group of high-income countries and focus just on those high-income countries with a population over 20 million. In total that gives us 13 countries. 

The conclusions are similar. The country remains an all-time outlier when it comes to cases and on the mortality side is it a current outlier but there are several large high-income countries that have indeed done worse, including in the more recent period of Omicron. 

Finally, let’s repeat the above analysis and apply it to the cumulative numbers. We can see that there’s been a dramatic catch-up on the cases side, especially when we consider South Korea’s peer group of large countries. Thankfully, on the mortality side, Korean numbers remain low in international comparison. That is because the country has managed to keep mortality at minimal levels prior to the current outbreak and because it has achieved high levels of primary and booster vaccination at the time of Omicron. 

We should caveat the above discussion by noting that countries of course differ in terms of testing, where the overall availability of tests is a factor as is the question whether the results of rapid at-home tests find their way into the statistics. South Korea’s has recently expanded rapid test efforts, which is likely to tilt the results upwards somewhat compared to other countries. 
The developments in South Korea are reminiscent of what is happening more broadly in the EAP region. The region includes several countries that have managed to contain or suppress the virus very well until Omicron came. Luckily South Korea was well prepared in terms of its vaccine coverage levels, which helped compensate for the fact that the vast majority of its population did not acquire immunity through prior infection. 
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