ðw i À w iÀ1 Þ t¼t final
j
% 7aS 1
ð7:21Þ
To calculate the right part of Eq. (7.21), we can use the values of SIR parameters
presented in Table 6.25 (second prediction for the world). The result ðw i À
w iÀ1 Þ t¼t final
j
% 1:6 shows that first wave of the pandemic must end with almost zero
values of w i À w iÀ1 .
Almost zero weekly (and daily) increase in the global number of COVID-19
cases was observed in late February 2020. It is difficult to see it in diagram 7.6, but
clearly visible in Fig. 6.29. We cannot treat this period as the end of the first
pandemic wave, since too many cases in many countries were not detected in this
period (compare magenta solid line and “triangles” in Fig. 6.29). After March 2,
2020, the values w i À w iÀ1 increased almost monotonically. A slight minimum is
visible only around August 17, 2020 (see Fig. 7.6). It means that next waves of
pandemic started before the first waves ended. We will discuss this issue in details
later.
Here we can try to use the time moment t B corresponding the minimum of
w i À w iÀ1 as an estimation of the last day of the global first wave and for the WHO
regions as well. The values t B corresponding to the accumulated number of cases V B
are listed in Table 7.5. It can be seen that global value of V B exceeds the theoretical
estimation V 1 (see Table 7.1) almost three times. Let us analyze the situation in
individual regions.
Figure 7.7 illustrates that the first wave of the epidemic probably ended in late
September 2020. Compared with the global dynamics, the minimum of values
w i À w iÀ1 is much lower than the maximum figures. The first wave of the pandemic
in the WHO African Region is much more pronounced than in the world (compare
Figs. 7.6 and 7.7), but the next (or subsequent) pandemic wave/waves in Africa
also began before the end of the first one.
Figure 7.8 illustrates that the minimum of w i À w iÀ1 values corresponds to the
beginning of September 2020 and is not much lower than the maximum figures
corresponding to mid-July. The first wave of the pandemic in the WHO region of
the Americas is much less pronounced than in Africa. Probably in the Americas,
some subsequent pandemic waves began before the end of the first one. This is also
evidenced by much higher values of V B =N pop compared to other regions and the
world as a whole (see Table 7.5).
Figure 7.9 illustrates that the minimum of w i À w iÀ1 values corresponds to the
beginning of August 2020 and is rather lower than the maximum figures corresponding to mid-June, but the first wave of the pandemic in the WHO Eastern
Mediterranean region is less pronounced than in Africa. Probably in Mediterranean,
some subsequent pandemic waves began before the end of the first one.
Figure 7.10 illustrates that the minimum of w i À w iÀ1 values corresponds to
rather long period in June 2020. This fact is in good agreement with the calculations
for the last day of the first wave performed in the previous chapter for many
European countries and summarized in Table 7.6 (see also [75, 77]). This table
shows not only predictions for the last day of the first epidemic wave t final , but also
7 Comparison of the First Waves of the COVID-19 …
103
j
% 7aS 1
ð7:21Þ
To calculate the right part of Eq. (7.21), we can use the values of SIR parameters
presented in Table 6.25 (second prediction for the world). The result ðw i À
w iÀ1 Þ t¼t final
j
% 1:6 shows that first wave of the pandemic must end with almost zero
values of w i À w iÀ1 .
Almost zero weekly (and daily) increase in the global number of COVID-19
cases was observed in late February 2020. It is difficult to see it in diagram 7.6, but
clearly visible in Fig. 6.29. We cannot treat this period as the end of the first
pandemic wave, since too many cases in many countries were not detected in this
period (compare magenta solid line and “triangles” in Fig. 6.29). After March 2,
2020, the values w i À w iÀ1 increased almost monotonically. A slight minimum is
visible only around August 17, 2020 (see Fig. 7.6). It means that next waves of
pandemic started before the first waves ended. We will discuss this issue in details
later.
Here we can try to use the time moment t B corresponding the minimum of
w i À w iÀ1 as an estimation of the last day of the global first wave and for the WHO
regions as well. The values t B corresponding to the accumulated number of cases V B
are listed in Table 7.5. It can be seen that global value of V B exceeds the theoretical
estimation V 1 (see Table 7.1) almost three times. Let us analyze the situation in
individual regions.
Figure 7.7 illustrates that the first wave of the epidemic probably ended in late
September 2020. Compared with the global dynamics, the minimum of values
w i À w iÀ1 is much lower than the maximum figures. The first wave of the pandemic
in the WHO African Region is much more pronounced than in the world (compare
Figs. 7.6 and 7.7), but the next (or subsequent) pandemic wave/waves in Africa
also began before the end of the first one.
Figure 7.8 illustrates that the minimum of w i À w iÀ1 values corresponds to the
beginning of September 2020 and is not much lower than the maximum figures
corresponding to mid-July. The first wave of the pandemic in the WHO region of
the Americas is much less pronounced than in Africa. Probably in the Americas,
some subsequent pandemic waves began before the end of the first one. This is also
evidenced by much higher values of V B =N pop compared to other regions and the
world as a whole (see Table 7.5).
Figure 7.9 illustrates that the minimum of w i À w iÀ1 values corresponds to the
beginning of August 2020 and is rather lower than the maximum figures corresponding to mid-June, but the first wave of the pandemic in the WHO Eastern
Mediterranean region is less pronounced than in Africa. Probably in Mediterranean,
some subsequent pandemic waves began before the end of the first one.
Figure 7.10 illustrates that the minimum of w i À w iÀ1 values corresponds to
rather long period in June 2020. This fact is in good agreement with the calculations
for the last day of the first wave performed in the previous chapter for many
European countries and summarized in Table 7.6 (see also [75, 77]). This table
shows not only predictions for the last day of the first epidemic wave t final , but also
7 Comparison of the First Waves of the COVID-19 …
103