As of April 5, 2023, the coronavirus pandemic (COVID-19) had taken over 6.8 million lives and over 680 million confirmed cases globally (WHO 2023). In 2020, only 8.8% of global working hours were lost, which is equivalent to 255 million people losing their jobs (ILO Monitor 2020). By continent, employment was reduced by 8.3 percent in high-income countries, 7.3 percent in upper-middle-income countries, 11.3 percent in lower-middle-income countries, 6.7 percent in low-income countries, 4.7 percent in the United States of America, and 4.1 percent in Africa (Gopinath 2020; Bundervoet et al. 2022). As a whole, job losses during COVID-19 were 12.8 percent, compared to job losses during the global recession of 2007-2009 (10 percent) or the financial crisis of 1997-2001 (8.6 percent). The coronavirus pandemic crisis has been one of the worst recessions (-3 percent) since the Great Depression (-1 percent) economic downturn (Shibata 2020, Gopinath 2020). The global economic loss (GDP) in 2020 and 2021 was 9 trillion US dollars, which is greater than that of Japan and Germany (Gopinath 2020).
The rapid development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has proven to be an important contribution to reducing both viral transmission and disease burden (Gupta et al. 2021). However, concerns related to vaccine equity have become the greatest obstacle to addressing this global pandemic and potential future pandemics. According to the Director-General of the World Health Organization (WHO), 1 in 4 people are vaccinated against COVID-19 in high-income countries (HICs), while 1 in 500 people are vaccinated in low- and middle-income countries (LMICs) (Upadhyay et al. 2022). In September 2020, the WHO planned to initially allocate the COVID-19 vaccine to countries in proportion to their population size. After countries receive COVID-19 vaccine doses for 20% of their population, their COVID-19 risk will be considered for successive vaccine distribution (Herzog et al. 2021). Countries were also permitted to pursue bilateral contracts with vaccine manufacturers, which resulted in an uncoordinated approach and competition between countries for COVID-19 vaccines on the market (Herzog et al. 2021). Furthermore, a study published in The Lancet Infectious Disease reported that if no vaccines had been distributed, an estimated 20 million lives would have been lost in the first year (Watson et al. 2022).
The development of novel coronavirus disease 2019 (COVID-19) vaccines has been quicker than the development of previous vaccine inventions (Keni et al. 2020). Due to the complexity of vaccine development, it can take up to 10-15 years for a vaccine to be developed (Cohut 2020). However, COVID-19 vaccine development took less than a year, mainly because of worldwide cooperation (Cohut 2020). The Pfizer vaccine was the first vaccine that received emergency use authorization against COVID-19 from the Food and Drug Administration (FDA) on December 11, 2020 (Cohut 2020). Additionally, the WHO has approved and publicized ten COVID-19 vaccines, including Pfizer/BioNTech, Oxford (AstraZeneca), Janssen (Johnson & Johnson), Sinopharm (Beijing), Moderna, Sinovac, Covishield (Oxford/AstraZeneca formulation), Novavax, Covaxin, and COVOVAX (Novavax formulation) (WHO 2022a).
COVID-19 vaccination has resulted in a reduction in COVID-19-related hospitalizations and deaths, especially among older adults (Moghadas et al. 2021). A growing body of empirical evidence has also shown a significant waning effect of vaccines against infections (and transmission) at 12-16 weeks, with both Delta and Omicron variants (Bardosh et al. 2022; Fabiani et al. 2022; Chemaitelly et al. 2021), even with third-dose shots. According to a WHO 2022d report, as of 19 August 2022, a total of 12,814,704,622 vaccine dose vaccine doses have been administered. Vaccination against COVID-19 and prior infections has resulted in the mitigation of disease outbreaks (Moghadas et al. 2021; Suthar et al. 2022). Although equitable access to COVID-19 vaccines is critical to contain the pandemic, the global percentage of people fully vaccinated with the last dose of the primary series of the vaccine was 62.47%, with the highest percentage in the Western Pacific WHO region (83.98%) and the lowest in Africa (19.27%) (WHO 2022f).
A comparison of the vaccine acceptance rates among low-, middle-, and high-income countries revealed that the average vaccine acceptance rate in low- and middle-income countries (LMICs) was greater (80.3%) than that in the United States (64.6%) (Machingaidze and Wiysonge 2021). This study, therefore, assesses vaccine equity, distribution, and cases in global southern countries4, and the findings will inform governments, policymakers, and pharmaceutical companies on these issues. Furthermore, this study provides insights for future and current equitable access to pandemic vaccines, as 2.8 billion people around the world are still waiting to receive their first shot of the coronavirus vaccine as of March 7, 2023 (UNDP 2022). Therefore, this study uniquely contributes to the distribution of pandemic vaccines in both current and future contexts by using globally representative data from high-income, middle-income, and low-income countries and providing empirical evidence.
The study employed event regression and difference-in-differences estimation strategies where such techniques allow us to exploit variations in timing by geographical units. The date of COVID-19 vaccine confirmation by the WHO was used as an information event/policy to assess the variation in timing across countries. The data used in the study included various dates when vaccines were available in different countries, including the first available date and the first available date for certain age groups/disaggregated by age. The inclusion of these various dates in the data facilitated the application of event study regression and difference-in-differences estimation techniques. Additionally, time and country fixed effects were used to control for certain factors.
COVID-19 vaccine equity, availability and distribution
The United Nations Development Program (UNDP) defines vaccine equity as “a means that vaccines should be allocated across all countries based on needs and regardless of their economic status”. There is equal access to vaccines without any distinction in race, religion, economic status, or social condition (UNDP et al. 2022). However, the COVID-19 pandemic has disproportionately affected racial and ethnic minorities (White and Grimm 2022; Scott et al. 2021).
Although several organizations have signed a vaccine equity declaration, the inequitable distribution of COVID-19 vaccines is still a major public health problem, especially in LMICs (WHO 2022b). To minimize disparities related to the COVID-19 vaccine, the promotion of vaccine equity and increasing access are essential (Scott et al. 2021).
The main reasons for vaccine inequities are vaccine access and vaccine hesitancy (White and Grimm 2022). Additional reasons for vaccine inequity include the affordability of vaccines for poor countries, the control of vaccines by wealthy countries, the control of global vaccine production by a small number of countries, and challenges with the distribution and administration of vaccines due to poor infrastructure in low- and middle-income countries (O’Leary and Tsui 2021). Moreover, an interrupted cold chain due to power supply problems and a lack of adequate freezers is another major problem in getting COVID-19 vaccines to low- and middle-income countries (LMICs) (The Lancet Infectious 2021).
A report by the UNDP, WHO, and the University of Oxford showed that low-income countries started their vaccination campaigns an average of two months later than did high-income countries. Although the WHO has called for vaccine equity, there are still challenges related to vaccine distribution in LMICs (WHO 2022 g). For instance, as of May 11, 2022, 72.08% (3 in 4) of people in high-income countries have been vaccinated with at least one dose. However, in low-income countries, only 17.4% (1 in 6) of people receive at least one dose (UNDP et al. 2022), despite a greater willingness to receive COVID-19 vaccines among people in LMICs (Solís Arce et al. 2021).
The inequitable distribution of vaccines exacerbates existing socioeconomic inequalities, particularly in LMICs, leading to higher rates of COVID-19 cases in these countries (UNDP et al. 2022). Moreover, unequal access to vaccines also increases the risk of new COVID-19 variants (Afolabi et al. 2021; UNDP et al. 2022). Furthermore, a study conducted in Ohio, USA, showed the effectiveness of the vaccine lottery program in increasing COVID-19 vaccination (Brehm et al., 2022).
The majority of vaccines administered thus far have been in high- and upper-middle-income countries (WHO 2022b). This global unequal distribution of vaccines contributes to low vaccine uptake. For instance, as of May 11, 2022, the percentage of individuals fully vaccinated with the last dose of the primary series in high-income countries was 73.67%, while it was only 13.03% in lower-income countries (WHO 2022f). As of May 11, 2022, there were a total of 516,476,402 confirmed cases of COVID-19, including 6,258,023 deaths globally (Johns Hopkins University and Medicine, 2022). COVID-19 vaccination is essential for mitigating new cases and deaths. A study conducted in the United States on the impact of vaccination on COVID-19 outbreaks showed a reduction in the overall attack rate from 9% to 4.6% and a reduction in adverse outcomes, including death (Moghadas et al. 2021).