Title: Global, Regional, and National Estimates of Target Population Sizes for Covid-19 Vaccination: Descriptive Study
Authors: Wang et al., 2020
Journal: BMJ
Date: 12/15/2020
Tags: Covid-19 vaccine, allocation schemes
Reviewer: NC
Link: https://www.bmj.com/content/371/bmj.m4704
Summary: This descriptive study utilized country specific data to identify target population sizes for an effective global immunization plan for Covid-19. The study utilized three allocation schemes targeting essential workers, high risk individuals, and high transmission groups. To gather estimates for the target groups, researchers used data for 194 World Health Organization member states from sources such as the World Health Organization, World Bank Group, and the census. In addition, researchers used a systematic review and meta-analysis to estimate the willingness to accept the Covid-19 vaccine and information from major pharmaceutical companies to estimate production capacity of the Covid-19 vaccine. After analyzing country specific data, researchers organized the total population into various priority groups in relation to the three allocation schemes. From summing the priority groups, researchers calculated a total target population of 5.1643 billion people (95% CI: 5.1263 - 5.2023). Researchers estimated 60 - 80% vaccine coverage, bringing the target population to 3.1 - 4.1 billion people. Researchers also reported geographical disparities, including a high concentration of essential workers in the Western Pacific, the Americas, and Europe and a high concentration of individuals at greater risk for Covid-19 in South East Asia and the Western Pacific. The study estimated 10.3 billion doses of the Covid-19 vaccine for high risk individuals and those in targeted occupational groups and 15.6 billion doses for a universal vaccination program. Researchers highlighted how the duration of vaccination programs will vary globally due to disparities in supply and vaccine production capacity. Researchers also emphasized the need for affordable pricing of the Covid-19 vaccine and effective allocation plans to increase access to the vaccine and approach herd immunity.

Limitations: A lack of data for 2020 affected population estimates for several countries. Researchers were unable to analyze variations of target populations within countries. A lack of data also limited estimates of target population for essential workers such as those working in finance/economy and of target population by race and ethnicity. Researchers did not subtract essential workers <60 years old with underlying conditions from the group of adults with underlying conditions. There also remains uncertainty regarding including individuals with a past Covid-19 infection in the priority groups.

Takeaways: This study outlines a possible vaccine allocation strategy for Covid-19. The study also emphasizes how the size of target populations varies by region and vaccination goal. Vaccine production capacity and supply must be considered, particularly for regions that may struggle to meet the demand for the Covid-19 vaccine.