How is the fourth wave of the COVID-19 epidemic different from the previous ones, and what is similar about them? Statistics show that within a month and a half, the number of detected SARS-CoV-2 coronavirus infections has more than tripled, and the growth dynamics can reach previously rare values. The new wave of the epidemic, however, is starting from a lower level than the previous two, and so far there is no sign of an increase in the death toll.
The Ministry of Health publishes reports with data on the epidemic every day from 10.00 am. Each such report contains information collected from the previous day. This is because Minister Adam Niedzielski was able to give the number of new, confirmed infections in a radio interview two hours before the official announcement. It also means that data for the period from August 1 to August 31 are included in ministerial reports published from August 2 to September 1.
In August, a total of over six thousand Poles contracted the SARS-CoV-2 coronavirus. How many exactly is harder to say. The sum of the infections from all 31 reports is 6062, but if from the number of infected from the beginning of the epidemic to the end of August (in the release of September 1 it was 2,889,036) subtract the number reported at the end of July (2,883,029 in the information of August 1) , it comes out 6007. Where did these discrepancies come from? In its daily tweets, the ministry repeats the reservation that corrections are introduced in the ICT system on an ongoing basis.
The number of fatalities that the epidemic took in Poland in August is more certain – both counting methods indicate that exactly 97 people died.
These are numbers which, in comparison with the experiences of the last dozen or so months, do not arouse fear in many people. On May 7, only one daily report of the Ministry of Health reported 6,047 new confirmed coronavirus infections (and 453 deaths), and on June 9 we had 108 deaths (with 428 infections). In November 2020, at the height of the second wave, and in March 2021, when the third wave was approaching the peak of the third wave, we sometimes had 100,000 new infections in four days, and there were more than 700-800 deaths.
Coronavirus in Poland. More and more new infections
However, what can be seen in the statistics from the last weeks is the increase in new coronavirus infections. In the report for Wednesday, September 1, we had 366 new confirmed cases, while on August 4, the first Wednesday of the month, only 164. Why do we compare Wednesday to Wednesday? Because the numbers of infections and (even more) deaths reported by the ministry fluctuate very strongly depending on the day of the week – the data flowing into the system is usually understated on Saturdays, Sundays and holidays, and these deficiencies are filled at the beginning of the week.
Therefore, to illustrate the scale of the epidemic, specialists usually use a rolling average of new confirmed coronavirus infections calculated on the basis of data from the last seven days. After the third wave of the epidemic in Poland, which peaked on April 1 (an average of almost 28.9 thousand infections per day), this rate dropped until the first half of July, to the level of 78 infections per day, first on July 10 and again on July 14. At the beginning of the following month (August 2 report) it was on average 128 infections a day, and at the end (September 1 report) – 258. More than three times more than in mid-July and twice as many as at the beginning of August.
Last month, the average daily number of infections increased systematically – there were only three days when it dropped for a moment and then jumped up again the next day.
Coronavirus – growth dynamics
The second indicator used by experts and the Ministry of Health to describe the epidemic is the dynamics of the increase or decrease in the number of new infections. This percentage is calculated on the basis of the data from the reports for the given day and the week before. For example – on September 1, the health ministry informed about 366 new, confirmed infections, a week earlier it was 234. This means an increase of 132 infections, or 56.4 percent. On that day, we could speak of a 56% growth rate of new infections.
Throughout August, this indicator averaged less than 20 percent. This means that on average, there were one-fifth more infections each day than the week before. But this is a big simplification. In addition to the three days when the dynamics was negative, there were also such announcements of the ministry, from which it was possible to calculate that it grew by a third (August 8 report), by 41 percent (August 30) or by more than a half (August 3, 1 September). In the August 16 report, the dynamics was 100 percent, i.e. there were exactly twice as many infections (128) as the week before (64). We dealt with such or greater values only in the first month of the COVID-19 epidemic in Poland and in September and October 2020, when the second wave began to resemble a tsunami. During the third wave, dynamics above 50 percent only happened twice, with March 15 being almost 77 percent.
The fourth wave of the epidemic – the starting point
What distinguishes the second, third, and currently rising fourth waves of the epidemic are also the starting point. From the first coronavirus infection detected in Poland, on March 4, 2020, the average daily number of new cases increased – though not continuously – almost until the end of the summer holidays. On August 27, we had an average of 759 infections a day. This was followed by a two-week period of decline – on September 11, the daily average was 461 infections. This was the start of the second wave of the epidemic, which peaked on November 11 with an average of 25,615 infections confirmed each day.
The period of decline – also interspersed with certain fluctuations – lasted until February 9, 2021, to an average level of 5,215 infections per day. From then on, the Third Wave climbed to a level where the average number of cases per day, based on seven days of data, was 28,873, almost 13 percent higher than in the fall of 2020.
The third wave fell by the first half of July, to the already mentioned level of 78 infections per day. This decline was basically uninterrupted – almost all fluctuations in the chart can be explained by understated reports during the Easter, Picnic and Corpus Christi periods. Since July 14, the average number of new cases has been increasing again, slowly, but there is virtually no disturbance in this trend.
Subsequent waves of the epidemic began at completely different levels – an average of 461 infections in September 2020, 5215 in February 2021 and 78 in July. We already know the fourth wave of the epidemic in seven weeks increased more than three times. How was the second and third wave? It would seem that such a comparison will not say anything, because the latest wave will benefit from the so-called low base effect, but it is exactly the opposite. Paradoxically, the second wave took less than three weeks to reach levels over three times the starting point. The third wave, starting from a much higher point, did so in five weeks.
Coronavirus in Poland – how the number of deaths changes
The fourth wave of infections also differs from the previous ones in that so far it has not been seen to be followed by another wave of deaths. In the fall of 2020 and spring 2021, the death toll of the epidemic was at its highest about two weeks after the peak of the average number of new infections. If the second wave of infections peaked on November 11, 2020, the average number of deaths, also calculated from the past seven days, peaked on November 25, with an average of 505 deaths per day. In spring, following the peak of the third wave of infections on April 1, the highest average deaths were recorded on April 14, at 603.
Now that the average number of infections has risen over the past seven weeks, the average number of deaths has not increased significantly. Throughout August, it fluctuated between two and three people a day. Only in the September 1 report it exceeded four, but it is too early to draw conclusions from this.
COVID-19 epidemic – situation in hospitals
While experts keep repeating that it is not beds that treat patients, data from hospitals should be taken into account. At the end of August, we had less than eight percent of the beds dedicated to treating COVID-19 patients and less than 10 percent of the ventilators dedicated to that purpose. The monthly average was nearly six and almost eight percent, respectively.
We do not know how it was at the beginning of the second wave, because it was only on October 23, 2020 that the Ministry of Health began to provide data on beds and ventilators, broken down into available and already used by patients. By contrast, when the third wave of infections began in early February, the occupancy of beds and respirators ranged from 40 to 50 percent, with the pool of beds over 27,000 and respirators over 2,600.
At the height of the third wave of the epidemic, nearly 80 percent of the hospital beds and ventilators dedicated to the fight against COVID-19 were in use. This happened despite the fact that the influx of patients was accompanied by an increase in the pool of equipment intended for them – to 46,000 beds and over 4,500 respirators. Currently, 6,000 patients are waiting for patients in covid wards. beds and less than 580 respirators.
Main photo source: Leszek Szymański / PAP