COVID-19 booster vaccination has not decreased access for low-income countries.

The Food and Drug Administration and Centers for Disease Control and Prevention have clarified their stance in support of booster vaccinations for COVID-19. However, there are legitimate ethical concerns that booster campaigns in higher-income countries may limit access to primary vaccinations in lower-income countries. Specifically, ethical arguments have suggested that implementation of booster campaigns will limit the available vaccine supply in other countries.

Because vaccine access depends on factors beyond adequate supply, we hypothesized that booster campaigns might not exacerbate disparities for low-income countries. The purpose of this study was to determine how booster vaccination campaigns in higher-income countries have affected primary vaccination rates and survival in low-income countries.

International vaccination information from Our World in Data was queried for daily booster administrations and primary vaccinations. Countries were categorized into low-income, lower middle-income, upper middle-income, and high-income cohorts based on current World Bank classifications. Temporal trends of COVID-19 booster vaccinations in higher-income countries were compared to concurrent temporal trends of COVID-19 primary vaccination rates in low-income countries. New infections and death rates due to COVID-19 among these cohorts after booster vaccine implementation were also analyzed.

Vaccination reports from 224 countries and territories were available. Booster vaccinations started as early as July 2021. During the 16 weeks since booster campaigns have been implemented, there have been 52 million booster vaccines administered in higher-income countries.

Contrary to widespread concerns, low-income countries have continued to increase primary vaccinations concurrently with higher-income countries implementing booster campaigns (Fig. 1 ). During these 16 weeks, low-income countries increased their primary vaccination rate by 257%, outpacing the rates of high- and upper middle-income countries. High-income countries had a 280% increase in new cases of coronavirus infection, whereas low-income countries have had only a 145% increase in new cases of coronavirus infection during the booster campaign interval. High-income countries had a 368% increase in coronavirus deaths, whereas low-income countries have had only a 152% increase in coronavirus deaths during the booster campaign interval.

Fig. 1

Trends in low-income vaccination new rates versus higher-income booster vaccination rates.

Global vaccine inequity is a perennial problem, and this has been underscored by the COVID-19 pandemic. To date, nearly half of the population of high-income countries has had at least one dose of vaccination, compared to 1 in 27 people in low-income countries. Of the total 17.9 billion vaccine doses available worldwide, high-income countries have secured more than the total procurement of all upper middle-, lower middle-, and low-income countries combined.

Despite these alarming figures, claims that vaccine booster campaigns by higher-income countries will constrain the supply of vaccines in lower-income countries remain unproven. Although global initiatives have been implemented to mitigate distribution inequity, vaccine vials often go unused. For example, African nations have had to destroy nearly half million doses of expired vaccines since the beginning of the pandemic. Reports of unused vaccines in low-income countries demonstrate that there are additional challenges beyond merely ensuring adequate supply to these regions.

The top of the supply chain includes vaccine research, development, manufacturing, and production. The lower end of the supply chain requires infrastructure for transportation, storage, delivery, and administration. These downstream supply chain components have become the current barriers to adequate vaccine access in lower-income countries. For example, mRNA vaccines require transportation and storage in freezing temperatures until injection. Ensuring that transportation lines and storage centers have the technology to provide uninterrupted temperature of −70 °C throughout the downstream supply chain can be challenging and expensive.

Given the lack of pre-existing infrastructure, significant healthcare spending has been necessary to adequately meet COVID-19 vaccine demand in low-income countries. Prior to the current pandemic, only 11% of countries in Africa and Southeast Asia had established adult vaccination programs. During the COVID-19 pandemic, high-income countries increased their healthcare spending by only 0.8% to vaccinate 70% of their populations, whereas low-income countries increased healthcare spending by 56.6% for significantly lower vaccination rates.

Continued efforts are necessary to enhance supply chain infrastructure for the delivery and administration of vaccines in low-income countries. However, these results demonstrate that global booster campaigns have had no detrimental impact on primary vaccination rates in low-income countries. Continued vigilance is necessary to monitor resource utilization and ensure that booster vaccination campaigns do not disrupt primary vaccination efforts in vulnerable regions.