Vaccine equity across borders can be usefully assessed by comparing vaccination progress across the World Bank income classification of countries. In the charts that follow we look at inequalities across income groups (high-income, upper-middle-income, lower-middle-income and low-income countries: HICs, UMICs, LMICs and LICs). We focus on progress towards vaccinating the total population.
The poorer half of the world remains the most poorly vaccinated
Coverage ratios in LMICs and LICs, which together represent 52% of the global population, are much lower than HICs and UMICs. This inequality continues to be true for primary vaccine coverage (even though LMICs have narrowed the gap) and it remains especially true for booster vaccination.
We show in the chart below the primary vaccine coverage ratio in bars, which simply measures total doses administered divided by the total population. For full coverage we need a ratio of 200% (or 2). To make sure that this threshold applies also for countries that use single-dose protocols (like J&J or CanSino), we convert doses under such protocols into double-dose equivalents (multiplying them by 2). That way a 200% ratio means full vaccination for everyone. We also show the booster coverage ratio as dots, which are simply booster shots per 100 people.
Booster inequality is a spitting image of what transpired with primary vaccination
We can also look at the evolution of these coverage ratios over time. The charts below show how primary and booster coverage have evolved by income group and over time.
On the primary series, HICs initially took the lead, but UMICs caught up very quickly. The latest values for LMICs and LICs imply a lag of about 6 and 12 months, respectively. However, unfortunately, we see that vaccination momentum has diminished across all income groups, including where much more progress would need to be made.
A similar pattern holds for the booster series. HICs and UMICs have raised coverage almost in tandem. But LMIcs and LICs are seeing huge lags and very low coverage ratios. Interestingly, though not surprisingly, booster inequality follows a very similar pattern as primary vaccine inequality did earlier during the vaccination campaign.
Let’s not forget the huge dispersion of experiences at the country level
We’ve so far looked at where we currently are in terms of vaccine coverage and how we got here. In doing so, we’ve depicted the situation at the level of the income aggregates of the World Bank. These aggregates are population-weighted, i.e. countries with a large population will feature more prominently than countries with smaller ones.
The charts below provide a more granular picture at the country level by looking at dispersion of vaccine coverage across and within income groups. The center points of the bubbles represent country observations for primary coverage (first chart) and booster coverage (second chart). The size of the bubble grows with population size, which helps us to appreciate the absolute size of the vaccination challenge.
As for the primary series, we can see that HICs and LICs are more clustered around their respective means. whereas there is more dispersion around the mean for UMICs and LMICs. We also note that the mean for UMICs and LMICs continues to be pulled up by China and India, which have a disproportionate effect on the mean given their population sizes.
For booster vaccination, HICs and UMICs are more dispersed than LMICs and especially LICs, which reflects that booster campaigns have not started off with equal intensities in the richer half of the world whereas in the poorer half progress has been limited almost universally.
Many poorer countries have continued to lag with little progress
Given the disproportionate role of China and India in the population-weighted averages, it is also useful to adopt the more granular country-by-country perspective when looking at the evolution of vaccine coverage over time while maintaining the grouping by country income levels.
In what follows, we present dynamic visualizations that examine the evolution over time of the dispersion in vaccine coverage across and within income groups. We do so for both the primary series and boosters. The chart is divided into the four quadrants of the World Bank income classification. Within each income group and at each point in time, countries are sorted by coverage ratio, which has the effect of showing the gradual progression of vaccine coverage of the entire income group.
The visualizations show both the extensive and intensive margins of vaccine equity. The extensive margin measures whether have started vaccinating. This is captured by the circular inner bar which measures the share of countries in each country group that have started, respectively, the primary and booster vaccination campaigns. The intensive margin captures the extent of vaccine coverage once countries have started inoculating their populations. This is captured by the blue bars within the circle.
Universal global coverage would occur when this donut-like visualizations turns completely blue. Alas, we continue to see huge gaps caused by the considerable lag in vaccination participation among poor countries (extensive margin) and their persistently poor vaccine coverage (intensive margin). Once again, the patterns for booster vaccination follow those observed in the primary series.
Whatever the underlying reason, the regressive nature of vaccine coverage remains highly inequitable
Undervaccination may derive from a variety of factors on the supply and demand side. In this post, we have equated the unequal progress of vaccination with a broad notion of vaccine inequity. We have proxied vaccination progress as revealed by the number of doses that have been administered while remaining agnostic of the underlying reasons for undervaccination.
Earlier on in the vaccination campaign, supply-side constraints turned out to be more binding than demand-side ones. As the world was ramping up the production of vaccines, the richer countries were first in line to receive them. Vaccine hoarding and nationalism were at the time primary contributors to vaccine inequity.
But vaccine inequity should not be merely equated with inequities arising from the unequal and unfair international distribution of vaccines. The broader set of factors on the supply side (e.g. logistical challenges in distribution) and the demand side (e.g. vaccine hesitancy) that drive undervaccination speak to unequal capacities across countries that reflect other inequities in global health and international development, as is discussed further in this blog.
Vaccine equity has not improved much. The revealed capacity of the world to vaccinate its population remains blatantly regressive. The reasons for this outcome are complex and relate to vaccine inequities in the strict and broader sense. But the fact that the poorest countries remain the most underprotected is an undesirable outcome no matter how one looks at it.