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Trying to deal with striking differences in coronavirus mortality in Italy and South Korea

The first confirmed case of coronavirus in Italy and South Korea around January 20. The population is 60M in Italy, 51M in South Korea.

At the end of March 11, 2020 in Italy, 12,462 confirmed cases and 827 deaths, ~ 6.6%. In South Korea - 7755, 61, ~ 0.77%. (numbers from here [1]).

In Italy, the situation is almost an order of magnitude worse (8.5 times). But why? Let's try to figure out at least partially.



Disclaimer I am not a medic or biologist.

As part of this text I will play for mathematics with the experience of bioinformatics.

Therefore, reasoning may not be relevant to reality. On the other hand, all the facts will be confirmed by pruflinki.

If you have facts with pruflinks - burn!

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So. To begin with, because of what numbers could be different at all. Then we will try to evaluate these effects.

  1. Different distribution of the population by age groups. Judging by statistics, there is a very significant dependence of mortality on age [2, 3].
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Judging by statistics, there is a very significant dependence of mortality on age [2, 3]. These numbers are from China. In Korea [9], the ratios are very similar, although the absolute values ​​are less.



In China, people with an age of 60+ give 80% of deaths, in Korea - 86%.
In Korea, 11.4% of the population is over 64 years old, and in Italy - 20.3% [7, 8].

If we assume that all mortality is in this age category, then this should give a factor of 20.3 / 11.4≈1.8.

In fact, it so happened that in Korea a significant part of the cases are young girls who are at low risk.

If we calculate the proportion of confirmed cases with an age of> 50, then we get the following numbers:
3021 / (3021 + 4492) ≈40% for Korea [4], 39.2 + 37.4 = 76.6% for Italy [10] (the numbers are muddy, better than statistics found).

Again, if you transfer all lethality to this category, you get 76.6 / 40 = 1.92 (by the way, very close to 1.8, which is good).





Counting sick


In South Korea, there is quite a bit of testing now: on March 11, more than 220K tests were already conducted there [4], against ~ 60K in Italy [5] (see also [6]).

Koreans get 7755 / 220K≈3.5% infections per test.
The Italians - 12462 / 73154≈17%.

Accordingly, in Korea, the sample most likely has more mild cases that pass without complications.

But how to evaluate it? I could not figure out how to do this according to the data that I managed to find.

One could compare the recovery. Mild cases should go away in a couple of weeks, severe cases in 4-6 weeks.

But in Italy there are about 1000 recoveries, against 300 in Korea [1, 11]. Doesn't fit. If you look at the active very severe cases, then there are 1028 / 10590≈9.7% in Italy against 54 / 7470≈0.7% in Korea [11].

Perhaps these numbers just mean that in Italy there are actually about 1028 / 0.7% / 1.92≈76488 sick people, just most of them are sitting with a slight “SARS” at home and not shining.

In general, this can be believed, Hubei was able to get 50K in a month and a half, Italy could also be able to.

True, very big questions remain about the same understanding of the words “hard cases” in Italy and South Korea.

There is still subtlety, but hardly important.

Italians all who die naturally with the virus count as coronavirus deaths, regardless of the real cause of death. In any case, acquaintances from there wrote to me like that.
I have no information about Korea.

Treatment


In Italy, the number of hospital beds per person is 4 times less than in Korea [12].

Obviously, this also leads to the fact that a large proportion of severe cases are treated “at home”.

There is also evidence that patients with a low probability of survival simply do not have enough beds and equipment [13, 14, 15].

But the lack of hospitals in the sense should only affect acute cases, since there is no cure for the virus itself or a drug method in order to avoid pneumonia.

Acute cases are about 20% of all infections, including asymptomatic ones [16].

If suddenly doctors, beds, ventilators, etc. lacking just for a quarter of severe cases, this will be enough to explain all mortality in Italy.

I could not find exact data on this subject.

Strains


The virus mutates quickly enough. The current estimate is about 30 replacements per year. The strains in Italy and Korea are really a bit different [17]. True, they differ in just a few replacements.

They write that in the whole variety of mutations that the virus has encountered, two subgroups stand out: the so-called "S" and "L" by the designation of the amino acid that has been replaced. It all started with the “S” version [18], but by now in China there are already 70% of the “L” version. Moreover, among the available read genomes, the replacement S => L was noticed 6 times in completely independent virus branches.

They write that the L-version is more "evil". But judging by [17] the read genomes from Italy are “ordinary” S-ki.


Italian strains vs Korean


S and L versions of the virus and their territory


Variety of virus by country. The X axis is the date, the Y axis is the number of mutations, the color is the country.

Races and bad habits


I did not see any signs of a relationship between virus problems and races. But bad habits like smoking should influence. The virus enters the cell due to the ACE2 protein, which is more in the smoker's lungs. And the smoker breathes worse. However, more people smoke in Korea than in Italy: 2072 cigarettes per person per year versus 1442.

What to do


Who knows? Apparently, the most important part in the “treatment” of coronavirus is the prevention of a transition to a serious condition.

In general, I recommend the vidos of a well-known system biologist from Canada about this:


I personally know a person who knows her personally and praises her. So the information should be normal.

References


  1. Infection statistics
  2. Mortality distribution by age
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  12. 100,000
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  16. Johns Hopkins Medicine
  18. S L
  19. S L


If you have a large proportion of the population with an age of 60 and few free hospital beds, ventilators, etc., then if the virus spreads it will be very, very painful. A bit like Italy.

PS The genome of the virus


The genome of the coronavirus COVID-19 - takes about 7500 bytes. Weak to write a virus with a binary size <7.5KB, which will affect more than 100,000 computers? [20]

Okay, joking.

The ILOVEYOU virus was very close to this. Surely there are "winners".

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