My blog

During the plague, the hardest thing to bear is not the reports of the ever-increasing number of infections, nor even the images of the line of Italian trucks carrying away corpses. The hardest thing to bear is not knowing when it will end.

Man is of course a creature that is incredibly practical and effective at getting used to and adapting to the consequences of any tragedy, even a long-term one, but it is still difficult to fall asleep with the thought that nothing will change tomorrow or in a month.

Many wise doctors and scientists are spinning scenarios of possible developments. There are plenty of opinions, simulations, and predictions, but they differ greatly and there is no clear indication that any clearly probable scenario is emerging from them.

Well, I'll add my two cents and write what I read from the data describing the course of the disease so far. However, I'll immediately point out that, like all these scientists, I really know nothing about the future, and I don't claim to be able to read numbers better than others do.
Everything I write next is based on data from 20 March 2018 – I download these data from the European Centre for Disease Prevention and Control (www.ecdc.europa.eu).

Since the beginning of the epidemic, the virus has appeared in 165 countries around the world, with the total number of infections exceeding 20,000 in China and Italy, and 10,000 in five countries: Iran, Spain, the USA, Germany and France. In another 10 countries, it is greater than 1,000: South Korea, Switzerland, the UK, the Netherlands, Austria, Belgium, Norway, Sweden, Japan and Denmark. In 47 countries, the number of infected is between 100 and 1,000 cases, and in 101 countries, it is less than 100.

For the analysis, I took the countries with the highest number of infections counted from the beginning of the epidemic. I considered the first day of the epidemic in each country to be the day on which the number of infections exceeded 100. According to this definition, the epidemic has lasted in China for 62 days. In Korea - 28, in Italy - 26, in Iran 23, in Germany - 20, in France - 20, in Spain - 18, in the USA - 17, in Switzerland - 17, in Great Britain 15, and in Poland - 7 days.

Since the epidemic lasted the longest in China, and today it seems to be coming to an end there, I tried to see how the characteristics of the Chinese course of the epidemic compare to other countries.

When Chinese statistics are cleared of one disturbing component (the Chinese lowered the criteria for recognizing a person as infected for a dozen or so days during the epidemic, which significantly increased the number of infected people, but after a dozen or so days they returned to the original criteria), it turns out that the graph of the increase in infections in China is very clear. For the first 18 days of the epidemic, daily increases in infections grew linearly from zero to almost four thousand people, and then also linearly dropped to almost zero for the next 25 days. On the eighteenth day of the epidemic, we had the peak of the epidemic dynamics in China, and the acceleration to the peak was faster than the deceleration after leaving the peak. At the same time, the mortality rate - reported as a percentage of deaths of people with coronavirus in relation to the number of infected people in the following days (deaths and infections always counted from the beginning of the epidemic to the day of measurement) - decreased from 3.5% to 2.5% on the eighteenth day of the epidemic, and then systematically increased to over 4% on the sixtieth day.

In Italy, we have 25 days of the epidemic behind us. For half of that time, we were dealing with a geometric, and therefore more dynamic than in China, increase in cases of infection. In the second half, the increases returned to linear and stable. Mortality in Italy has been recording a steady and linear increase from 2% on the seventh day to almost 9% on the 25th day of the epidemic. For now, Italian statistics do not give any signs that this situation will change. In my opinion, the weather may be the salvation to stop the increases in Italy. I assume that the contagiousness of the coronavirus decreases with the increase in temperature, like for flu. For example, in Poland, the weekly contagiousness of flu decreases tenfold between winter and summer (in February about 200 thousand people, in August about 20 thousand).

It is worth noting that almost five hundred people died of coronavirus in Italy yesterday (473 people to be exact). Assuming that an average of 2,000 people die per day in this country of 60 million (in Poland, which has a population of 37 million, about a thousand people die per day, so in Italy it will be about twice as many), this means that Italy has reached a situation in which almost a quarter of those who died that day had coronavirus. I have one question. Has the overall mortality rate in Italy increased since the beginning of the year, and if so, by how much? If the daily death toll in Italy has increased by 500 people since January, this means that the coronavirus killed them, and if it has not changed, this means that the causes were different. Why doesn't Italy publish such data? Why doesn't anyone ask Italy this question?

In the third country in the world with the highest number of infections – Iran, the increase in infections and deaths is starting to fall. The epidemic has been going on for 23 days and reached its peak on the 18th day – like in China. It seems that Iran has passed its peak and the epidemic is starting to subside. There are interesting mortality statistics in Iran. They fell from 10% to 3% for the first 11 days and then rose for the next 12 days to 7%.

The statistics of illness and mortality in Spain are very similar to those in Italy. The epidemic began in Spain 8 days later than in Italy and so far it seems that it will develop in the Italian way.

In the United States, we have 17 days of the epidemic, but a very dynamic, geometric increase in the number of cases. It seems that the epidemic is only just starting there and in the short term the US may become the leader in cases. Interestingly, along with the geometric increase in cases, the mortality rate is falling - from 7% at the beginning to 1% currently.

In Germany, we have 20 days of the epidemic. So far, the growth curve has not shown great dynamics and has even stabilized in recent days. Germany has one of the lowest mortality rates - below a quarter of a percent. However, today, on the 20th day of the epidemic, something strange happened - a huge increase in infections was recorded in one day - 5,940 cases. Up until the previous day, there were about 8 thousand of them in total. At the same time, 30 deaths were reported, and so far their number was 13 in total. In the coming days, we will see what this means.
The French disease and mortality statistics are very similar to those in Italy. The epidemic began in Spain 6 days later than in Italy and so far it seems that it will develop in the Italian way.

The disease and mortality statistics in Korea are very similar to those in China. Korea is on day 28 of the epidemic, and the peak of its growth dynamics occurred earlier than in China - on day 12. At the same time, the mortality rate remained between 1% and 1.5%.
In summary, it looks like Asia is slowly shaking off the coronavirus, and Europe and the United States have peaks ahead of them. In my opinion, in a week or two, other countries will start to go through peaks, and a dynamic retreat of the epidemic will occur in 3-4 weeks, along with rising temperatures. However, this is probably more of a conjuring of reality than reading from the numbers...