Inequitable access to COVID-19 vaccines among countries that hosted trials

A Yale-led study reveals wealth-based disparities in COVID-19 vaccine access among the low and middle-income countries that participate in testing.
A COVID vaccine vial sitting on a world map.


A Yale-led study reveals that low- and middle-income countries that hosted clinical trials for COVID-19 vaccines are receiving proportionately fewer doses of these vaccines, suggesting that there are wealth-based disparities in COVID-19 vaccine access among countries that participate in testing.

The study, published Nov. 18 in JAMA Network Open, examines access in terms of regulatory authorization or approval as well as delivery of six unique COVID-19 vaccines listed for emergency use by the World Health Organization (WHO) as of Sept. 7, 2021. Clinical trials for these vaccines were completed in 25 countries and are currently ongoing in an additional 12 countries.

In an analysis of both completed and ongoing clinical trials for WHO-recommended COVID-19 vaccines across 37 countries, the researchers found that more than 90% of the tested vaccines had been authorized for use as of early September. They also found that over 90% of the countries that hosted clinical trials for COVID-19 vaccines had doses of tested vaccines delivered. However, among countries hosting completed clinical trials, high-income countries received enough doses to vaccinate a median 51.7% of their population ages 15 years and older compared with rates of 31% and 14.9% in low- and middle-income countries, respectively.

These wealth-based disparities we’ve found among countries whose populations have participated in testing of these vaccines reflect the broader disparities in COVID-19 vaccine access that we’re seeing worldwide,” says Dr. Reshma Ramachandran, a National Clinician Scholar at Yale School of Medicine and the study’s lead author. “As many lower income countries continue to experience inequitable shortfalls in COVID-19 vaccine supply amid the ongoing pandemic, efforts must be undertaken to ensure timely access to all countries, regardless of income group, including those hosting clinical trials.”

The researchers also identified significant variation in the number of countries that hosted completed clinical trials for the different vaccines. Two high-income countries participated in testing for the COVID-19 vaccine manufactured by Moderna, while 9, 10, and 14 middle- and high-income countries hosted trials for vaccines manufactured by Pfizer, Johnson & Johnson, and AstraZeneca/Serum Institute of India, respectively. With the exception of AstraZeneca/Serum Institute of India, high-income countries that hosted completed clinical trials for all other manufacturers received more doses to vaccinate larger median proportions of their populations.

Appropriately including low- and middle-income countries in research is an important goal, particularly when an experimental medicine or vaccine targets a disease or condition burdening a country, like COVID-19. However, inclusion must correspond with fair access to the benefits of research, otherwise it can be exploitation,” said Jennifer E. Miller, an assistant professor at Yale School of Medicine and co-author of the study.

The authors also examined vaccine access in countries hosting clinical trials through COVAX, a global initiative co-led by the nonprofit Gavi, the Coalition for Epidemic Preparedness Innovations (CEPI), and WHO, which aims to make COVID-19 vaccines and other health technologies more accessible in low- and middle-income countries. They found that, as of early September, COVAX has delivered a much larger proportion of procured doses to upper middle-income countries (78.8%) than low- (15.4%) and lower middle-income (38.8%) countries that tested these same vaccines.

Data for this study were extracted from the Airfinity COVID-19 platform and generously provided by Anthony Kamande and Max Lawson of Oxfam International, a member organization of the People’s Vaccine Alliance.

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