Corona waves
The 2nd wave mostly exhibited very low values of infected and dead. Some countries
rather differed in some of the dates; for example, Israel had the 3rd wave in September to October, Belgium had the 4th wave in November,
etc. The last, 4th wave now mostly continues to descend toward quite low values,
and possibly toward the epidemic break; in some countries, including France, Italy, Czechia, and
Belgium, the 4th wave is tailing, and the values continue to keep quite high.
Most victims belong to the 3rd wave, many also to the 4th one (in some countries closely overlapping with the 3rd one, e.g.,
in Sweden), and in some countries to the 1st one (e.g., Belgium,
Sweden).
The waves sometimes overlap and are difficult to distinguish. A long tail may indicate another wave; for example, the tail after the 4th wave in Czechia may indicate a 5th wave. Some countries differ; for example, Brazil seems to show two broad peaks, and India has one broad peak covering the period from April 2020 to February 2021. China, that has obviously never reported real data, shows only one small peak placed in February 2020. Of course, the shapes of the waves reflect the officially reported values and need not exactly show the real spread. However, the four-peaks pattern can be seen even on the whole world summary values.
Table 1 shows deaths per million people, ranging from
the highest values of nearly 2000 (BE, CZ, GB), down to a half (DE) or a third
(IL) in the European domain. The Far East countries, including, e.g., JP, KR,
TW or AU, show much lower values (60, 31, 40 or 35, respectively) probably
because of their geographic isolation and early closure. The values from
non-democratic countries are not reliable; the mean world value is 321 deaths
per million, which says nothing about the real situation; China, the country of
the virus origin, reports 3 dead per million.
The most
important parameter is of course the fraction of the infected population.
Curiously, none of 200 countries of the world, and the WHO neither, cared
to regularly obtain this value. Several isolated attempts to serologically
estimate this value occurred mainly during the early stage of the pandemic. From
the beginning it seemed very probable that the total number of people who had
been infected was somewhere between 5 times to 100 times higher than the number
of positively reported cases, often about 10 times (here). As for now, the most probable factor to
multiply the reported cases to obtain the infected fraction is between 6 and 10.
Table 1 shows rough estimation of the infected
population fractions in several countries for the factor equaling 8.
It seems probable
that between ¼ and ¾ of the population have already been infected by Cocid-19
in various developed countries, except for the mentioned isolated Far East
countries.
Differences
among the countries
Strict
measures have been applied in nearly all countries that are included in Table
1, and it is difficult to explain the difference between Germany and neighboring
Czechia. The fact is that the measures have been most liberal in Sweden, and
the death per million in Sweden is lower than in seven of ten Western countries
in the table. Among the factors affecting the differences are the ways of
registering and reporting the deceased and diseased, protection of the
endangered groups, namely senior citizens, and of course the general behavior
habits resulting from the local culture. Different viral strains or mutants might
have some effects too; similar timing of the waves in different countries
suggests that the latter factor might be involved.
Some
differences can be explained by the population age distribution. More than 90%
deaths belong to the age group of 65+; Sweden has 20% population in this group,
while Israel only 10%, so that Israel would be expected to have only half of
the Swedish mortality, which is exactly what Table 1 demonstrates (614/1262 =
0.49). Of course, the politicians like to ascribe the lower values to their
wisdom.
Covid-19
decline and vaccination
By 23 February
2021, the share of people who received at least one dose of a vaccine is 52% in
Israel, 27% in the UK, 13% in the US, and 4% in Germany, Spain, Italy, and
France (here). In most countries, the values of new corona
cases and new deaths now decline. The question is what the relation of the
decline and the vaccination is.
The numbers
of new cases and new deaths started to decrease in most countries between the
end of December 2020 and the end of January, as the dates of the 4th peak maxima show in Table 1. The vaccination against Covid-19 started in many
countries toward the end of 2020. Thus, the two events touch in time but do not
overlap. Table 2 shows ten first countries of Table 1 with their
4th peak maximum date, and with their population fraction being
vaccinated by at least one dose till said date.
The graph
of daily new cases in Israel shows a decreasing trend from around January 20,
when 1/3 of the population has been vaccinated by the first dose of the Pfizer
vaccine, and the graph of daily new deaths shows a decreasing trend from around
January 27, when ½ of the population has been vaccinated. Most people received only the first dose of
two doses separated by 3 weeks. The first dose confers 50% to 80% protection,
but only several weeks after delivery, and most of the vaccinated people had
got the dose very closely to the peak maximum date. In any case, the effects of
the vaccination on the 4th peak decreasing trend would naturally be
assumed.
To evaluate
how prominent the decreasing trend the last peak exhibits in the countries, the
percent decrease of the new cases and the new deaths by February 16, relatively
to the date of the peak maximum, was calculated (if the peak maximum has 200
new daily cases, and Feb 16 has 50 new cases, the % decrease is 150/200=75% decrease).
The decrease is between about 50 and 80%, except for Czechia and France where,
moreover, the values stagnate (see also Table 1, the column “4th peak ending”).
It might be
expected that high infected population fraction will result in the epidemic
ending (collective or herd immunity), and indeed, the estimated % of the
infected population well correlates with the case and death % decrease (see the
last two columns of Table 2). In case of Germany, Czechia and France, the
correlation is weak. As for Czechia, it seems that the population is thoroughly
infected (more than 30% tests are positive), so that no measures have any
effects, and the virus will end its work in the whole susceptible population; the epidemics may hopefully be over quite soon, after infecting the
last remaining susceptible victims; if that is true, no vaccination would be
needed there. France, still having many uninfected susceptible people (if the
estimation is correct), might expect a fight like that in Czechia, but the
vaccination may help in finishing the matter more peacefully. Germany may have
managed to keep a larger part of the population uninfected (if the estimation
is correct), but surely the country would have to fight some more waves in the
future, if not being helped by the vaccination.
Reviewing the vaccination timetable clearly shows that the fractions of the population who had been vaccinated were too low to explain the decreasing trends of the case and death numbers – in all countries except for Israel (see Table 2). This holds for the whole world (see Table 1). For example, India exhibits clear decline in the numbers of new cases and deaths, while only 0.8% population has got the first vaccine dose and 0.1% the second dose by February 23 (here).
Conclusion
The total
world values for new daily Covid-19 cases and new daily deaths show decline.
The last Covid-19 wave exhibits a clear decrease toward minimal new cases and deaths values for
example in Switzerland, Spain, and Germany. The new deaths go to zero in Sweden. Also, populated countries like
Brazil and importantly India, show a clear decline of the values. The trend
started incidentally at the same time as the current vaccination efforts
started, but before any substantial part of the population was vaccinated. The
only exception is Israel, where a third or a half of the population got the
first vaccine dose (a small part of the population got the second dose) when the decline started to be
perceptible, so that the vaccination might or might not affect the decline
there.
It is not
clear whether another Covid-19 wave would come without the vaccination or not.
In some countries, like Czechia, the epidemic would probably end even without
vaccination, due to a large segment of the infected population; the epidemic
might continue till attaining herd immunity in many other countries, such as France
and even Germany; in East Asian countries and Australia, the epidemic would
hardly stop without continuing hermetic closure or without the vaccination.
Anyway, the world decline of the new Covid-19 cases and deaths that started in January was interestingly not a result of the vaccination.
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