An overview of COVID-19 global epidemiology and discussion of potential drivers of variable global pandemic impacts

Abstract

With a WHO-estimated excess mortality burden of 14.9 million over the course of 2020 and 2021, the COVID-19 pandemic has had a major human impact so far. It has also affected a range of disciplines, systems and practices from mathematical modelling to behavioural sciences, pharmaceutical development to health system management. This article explores these developments and, to set the scene, this paper summarizes the global epidemiology of COVID-19 from January 2020 to June 2021 and considers some potential drivers of variation.

Figure 1.

Europe region. Under this WHO categorization of the European region, some non-independent territories (the Isle of Man, Jersey, Guernsey and Gibraltar) are listed in addition to the UK. Reproduced from WHO. Published figures showing new deaths reported to the WHO by week, per 1 million population, by WHO region. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 2.

Americas region. Reproduced from WHO. Published figures showing new deaths reported to the WHO by week, per 1 million population, by WHO region. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 3.

Western Pacific region. Reproduced from WHO. Published figures showing new deaths reported to the WHO by week, per 1 million population, by WHO region. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 4.

South-East Asia region. Reproduced from WHO. Published figures showing new deaths reported to the WHO by week, per 1 million population, by WHO region. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 5.

Eastern-Mediterranean region. Reproduced from WHO. Published figures showing new deaths reported to the WHO by week, per 1 million population, by WHO region. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 6.

Africa region. Reproduced from WHO. Published figures showing new deaths reported to the WHO by week, per 1 million population, by WHO region. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 7.

WHO-modelled estimates of global mean excess deaths (count), 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 8

Reproduced WHO figures showing modelled estimates of excess mortality by World Bank income bracket, 2020–2021. The chart has a baseline of zero, representing the number of deaths that should be expected on the basis of existing average mortality data from 2015 to 2019. The shaded area depicts the number of COVID-19 deaths that have been reported to WHO by countries. The lines depict the estimated excess mortality, dipping below zero when there is lower mortality than expected. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 9

Reproduced WHO figures showing modelled estimates of excess mortality by World Bank income bracket, 2020–2021. The chart has a baseline of zero, representing the number of deaths that should be expected on the basis of existing average mortality data from 2015 to 2019. The shaded area depicts the number of COVID-19 deaths that have been reported to WHO by countries. The lines depict the estimated excess mortality, dipping below zero when there is lower mortality than expected. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 10

Reproduced WHO figures showing modelled estimates of excess mortality by World Bank income bracket, 2020–2021. The chart has a baseline of zero, representing the number of deaths that should be expected on the basis of existing average mortality data from 2015 to 2019. The shaded area depicts the number of COVID-19 deaths that have been reported to WHO by countries. The lines depict the estimated excess mortality, dipping below zero when there is lower mortality than expected. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 11

Reproduced WHO figures showing modelled estimates of excess mortality by World Bank income bracket, 2020–2021. The chart has a baseline of zero, representing the number of deaths that should be expected on the basis of existing average mortality data from 2015 to 2019. The shaded area depicts the number of COVID-19 deaths that have been reported to WHO by countries. The lines depict the estimated excess mortality, dipping below zero when there is lower mortality than expected. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 12.

WHO-modelled estimates for cumulative excess deaths (mean) by World Bank income bracket, 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 13.

Reproduced WHO figures showing modelled estimates of excess mortality by WHO Region, 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 14.

Reproduced WHO figures showing modelled estimates of excess mortality by WHO Region, 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 15.

Reproduced WHO figures showing modelled estimates of excess mortality by WHO Region, 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 16.

Reproduced WHO figures showing modelled estimates of excess mortality by WHO Region, 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 17.

Reproduced WHO figures showing modelled estimates of excess mortality by WHO Region, 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figures 18.

Reproduced WHO figures showing modelled estimates of excess mortality by WHO Region, 2020–2021. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.