This dynamic chart shows the evolution of population-level coverage ratios among the countries that have started. Once again, there are large discrepancies across income groups. Each dot represents a country that is grouped according to the income classification. At 100% one would achieve full single-shot coverage; at 200% full coverage with two shots is achieved. For visualization purposes, the distribution is censored: values above 200% are replaced by the maximum of 200%.
The distribution of vaccine doses across countries is described on the basis of data on the actual doses administered. The reasons why the numbers may be low can vary widely and include international vs domestic factors as well as supply versus demand factors. At this moment in time, however, the most likely reason for low numbers is related to international supply bottlenecks.
An additional complication pertains to the differences in treatment protocols across vaccines. The vaccine landscape is diverse with different treatment protocols in terms of the number doses that need to be administered, the dosage of each dose and the length of time between them. Vaccines differ in terms of their efficacy and deviations from the prescribed protocol dilute efficacy in uncertain ways. This matters as countries consider to speed up vaccination by e.g. changing, reducing or delaying doses.
The approach taken here in the face of this diversity of possibilities is to express vaccines in double-dose equivalents. We convert all vaccines to a common denominator of the double-dose protocol. This means that for the purpose of considering whether someone has achieved full vaccination we require that two doses have been administered.
Double-dose equivalence is imposed on single-dose vaccines by simply multiplying the number of single-doses administered by two. In this way, when adding up single doses of single-dose protocols and single doses of double-dose protocols, we can keep the threshold of 200% vaccine coverage as indicating full coverage.
As of early March 2021, this adjustment makes virtually no difference as there is only 1 country (South Africa) in the universe of countries considered here that is administering a vaccine that has a single-dose protocol (Johnson&Johnson).
The FY2021 World Bank income classification lists a total of 218 countries/economies, where the term country, used interchangeably with economy, does not imply political independence but refers to any territory for which authorities report separate social or economic statistics. This lists includes a number of territories and dependencies with populations above 30,000 people, as per the World Development Indicators database.
We narrow this list down to 196 countries/economies by retaining only the member states of the UN, one non-member state with observer status (the State of Palestine listed as West Bank and Gaza in the income classification) and two members/observers in UN Specialized Agencies (Kosovo and Chinese Taipei listed as Taiwan, China in the income classification). The Holy See, Cook Islands and Niue are excluded as they are not included in the WB income classification. A further 22 territories and dependencies (21 HIC and 1 UMIC) are excluded from the WB income classification because they are not identified as members or observers of the UN and UN specialized agencies.
Note that the vaccination data is pulled from Our World in Data, which utilizes a slightly different universe of locations. In sticking with the above 196 countries and economies, we have made the following adjustments relative to the OWID universe: