Booster sufficiency for priority group by country and income

This chart provides a global snapshot of the booster sufficiency ratio for the priority group across countries by World Bank income classification.  

The ratio is defined as the total number of booster doses that have been administered to the total population divided by the size of the priority group in that population. The priority group includes all seniors aged above 60 and all health workers (physicians, nurses and midwives) below 60 – the latter age cut-off to avoid double counting. For further details on the concept and measurement of the priority group, see the note on the priority group in the background section below. 

The chart shows the extensive margin of booster sufficiency (whether countries have started to boost at all, which is represented by the circular inner and outer bars) and the intensive margin (the actual level of the sufficiency ratio, which is represented by the vertical bars for each country). The dynamic version of this chart shows how these margins have evolved over time. Note also that universal coverage on both the extensive and intensive margins would amount to this donut turning entirely blue. 

Note that booster sufficiency for the priority group does not measure actual vaccination of the priority group. 

• That is currently impossible to consistently assess at the global level given data gaps. Instead, it describes, on the basis of the size of the priority group and the number of doses administered, the extent to which the priority group could have been covered through the booster vaccination efforts up through the latest available data point. 

• It therefore measures, in a minimalistic way, whether the a proxy for the supply of vaccines (the total booster doses administered to the total population thus far) could have been sufficient to cover fully the priority group. 

Finally, the booster sufficiency ratio is censored at 100. Once the priority group can be fully covered with boosters administered, we consider that vaccine sufficiency (in the minimal sense of the concept) has been attained. Larger values are set at 100.