Commentary Article
How does COVID-19 influence global
mortality rates? It has been crucial to investigate the related factors which
govern the severity and spread [1]. World Health Organization (WHO) and UN
department of economic and social affairs have presented the results concerning
estimating global and COVID-19-related death rate [2]. WHO has obtained a
mandate to collect and analyze statistics on mortality, and then tracked the
progress of COVID-19 pandemic after Jan 2020 [3]. The estimation of excess
mortality has been an adequate measure for the overall impact of the crisis.
Excess mortality has been defined as the difference of the total deaths in a
crisis in comparison with those under usual conditions. It can account for both
of total death number and those of indirect impact including travel disruptions
or discontinuation of health services [4].
The excess mortality has been
considered as the approach for evaluating the mortality of short-term period
[5]. However, it seems to be difficult to find a universal effective method to
show perfect excess mortality [6]. Excess deaths include deaths from diseases
other than COVID-19. It could have been avoided if it was in usual year.
However, current situation has been shown medical shortages during the
epidemic. From a long-term perspective, the COVID-19 epidemic may lead to a
decline in cancer screening rates, and the lack of appropriate treatment for
chronic diseases such as hypertension and dyslipidemia. Furthermore, the
economic stagnation due to restrictions on activities may also have an adverse
effect [7]. Global excess deaths for COVID-19 were previously estimated to be
5.42 million. As to the latest report, however, the value was calculated to be
14.83 million for 2.74 times [7]. Wider variations exist in excess death
calculating from six regions of WHO.
Each country has reported its excess
mortality. It can summarize the burden of COVID-19 associated with presenting
public health policy and also needs in the future [8]. The group of COVID-19
Excess Mortality Collaborators have showed the crucial study. As a result, 18.2
million excess deaths spread across 191 countries and territories in the first
2 years of 2020-2021 [9]. As many
countries have data paucity, and then ensemble-based of estimating excess
mortality has been calculated.
Concerning European countries, the Euro MOMO would be recommended, which
means standard approach for monitoring mortality for Europe [10].
Concerning the data for Japan, confirmed COVID-19 cases (n=32,990,844) and deaths cases (n=70,923) are reported during 2020 Jan 3 – 2023 Feb 15 by WHO [11] (Figure 1).
Figure
1:
Japan Situation of COVID-19 in Feb 2023.
Among them, total vaccine doses were
administered (n=371,971,415) until 2023 Jan 5. In Japan, there was no excess
death in 2020, which was found to be negative value [12]. The negative
situation of excess death was persisted in Japan, which was rather rare case
over the world [13]. The reason was that Japanese people continued perfect
infection control measures with voluntary movement restrictions [14]. After
2021, excess deaths became from negative to positive values in Japan as well.
The cumulative excess deaths in Japan from Jan 2020 to Sep 2022 were estimated
to be 50-140 thousand. Compared to other developed countries, excess deaths
were extremely small. As to the hospital survey in Japan, 67 thousand patients
with COVID-19 were hospitalized [15]. Their characteristics were 54 years old
in mean, 53.0% of female ratio, serious mental illness as 3.27%. By fully
adjusted model, mental illness showed significant association with mortality as
odds ratio 1.49. Authors and collaborators have presented several reports on
COVID-19 [16,17]. In May 2023, the status of COVID-19 will be lowered from
category 2 to category 5. However, it does not mean that infection control
measure will become unnecessary.
During 2020-2021, data of total
excess deaths were found from all 194 countries. As a result, minus value of
excess death was observed in only Japan, Australia, New Zealand and Norway [7].
It showed some patterns for quality of mortality data, which were available
from each respective country, such as satisfactory fully data, partial data,
mixed data, no data, or not applicable. Global excess death during 2020-2021
seemed to have 13.2-16.6 million excess deaths [7]. This degree was more than
2.4-3.1 times than that of officially reported COVID-19-related deaths. About
80% of excess deaths were found in middle-income countries. In comparison with
previous data, more refined and detailed estimates were presented by adjusting
several factors for underlying trends for some countries [18].
Consequently, some problematic
inferences were performed. Regarding COVID-19, the severity, timing and
spreading within countries were not uniform, then detail investigation would be
required [19]. Thus, a variety of data were calculated from subnational to
national degree. As the interrelationships exist between the infection of
COVID-19 and influenza, calculating models are already observed which can
adjust the influenza-related mortality [20]. Then, novel approach method has
been proposed for the adjustment of excess mortality of COVID-19.
Mortality statistics are crucial data
for public health management. Recent report showed the estimated excess
mortality of COVID-19 from 191 countries and districts, associated with 252
subnational units for Jan 2020 to Dec 2021 [9]. From the reported data
worldwide, totally 5.94 million deaths from COVID-19 were observed for 2 years.
However, the estimated excess death would be 18.2 million (17.1-19.6, 95%
uncertainly interval) by COVID-19 pandemic. Globally excess mortality of
all-age by COVID-19 pandemic was estimated as 120.3 deaths (113-129.3) per 100
thousand population. Thus, excess mortality rate was calculated in 21
countries, which showed more than 300 deaths per 100,000 population.
In summary, excess mortality of
COVID-19 pandemic has been of political and scientific interest [21].
Furthermore, uncertainty and substantial heterogeneity are present in
estimation of excess mortality. This article will hopefully contribute the
development of research in COVID-19.