Stanford Researchers Document Progress, Missed Opportunities in Equitable COVID-19 Vaccine Uptake
Unequal COVID-19 vaccination rates in the United States have compounded existing disparities in cases, hospitalizations and deaths among Black and Hispanic populations. SHP researchers quantify how differential vaccine uptake by race and ethnicity within each US state produced substantial vaccination coverage disparities during the initial scale-up among older adults.
Coverage was one-third lower among Black and Hispanic adults than white adults after the first three months of the COVID-19 vaccination campaign in the United States. Strategies to reduce these disparities as vaccine supply picked up could have closed the gap by as much as 76% for Black adults — but actual progress fell well short of this goal.
On the other hand, there was considerable progress in reducing disparities for Hispanic adults, whose vaccination coverage had caught up to that among white adults by July 1.
These are the findings of a study by Stanford Health Policy researchers who have been using mathematical modeling and data analyses throughout the pandemic as part of the Prevention Policy Modeling Lab and SC-COSMO consortium. Their projects have been informing public health officials, hospitals, state governments, and policymakers as they have planned for and mitigated the impact of the virus that has taken more than 720,000 lives in the United States.
In a research letter published in JAMA Network Open on Oct. 20, the researchers note that unequal vaccination rates compounded existing disparities in coronavirus cases, hospitalizations, and deaths among Black and Hispanic populations.
“The disparities in vaccination among Black and Hispanic adults seen in this study highlight the urgent need to invest in policies and interventions to promote vaccine equity,” the co-authors write. “Our results additionally demonstrate the benefits of place-based targeting of efforts to promote vaccination uptake.” Although the analysis was conducted during the initial scale-up period of COVID-19 vaccination, the findings remain relevant as booster shots are rolled out across the country and eligibility is extended to younger-aged children.
The research team — Marissa Reitsma, a PhD student in health policy, and SHP faculty members Jeremy Goldhaber-Fiebert and Joshua Salomon — analyzed vaccination data collated from state websites and corrected for missing and inconsistent reports in order to develop comparable estimates of vaccine coverage by state and race/ethnicity over time.
Starting from their estimated coverage levels as of April 1, they considered different scenarios for what might have happened over the period that followed, after vaccine eligibility opened to all adults. They compared projections from three scenarios: continuation of unequal vaccination rates across different racial/ethnic groups from April 1 through July 1, 2021; what would have happened if there had been equal vaccination rates across all racial/ethnic groups; and what geographically focused efforts to double the vaccination rate among the most disadvantaged quartile of census tracts in each state might have achieved.
“By the time vaccine eligibility opened to all adults, it was clear that Black and Hispanic populations were under-vaccinated compared to white populations in the vast majority of states, in large part due to structural racism,” said Reitsma, lead author of the study. “With the Biden administration and many states making efforts to improve vaccine equity, we designed our analysis to assess how actual vaccination coverage levels compared to levels that would be expected if unequal vaccination rates persisted, if vaccination rates were equalized, or if vaccination rates were explicitly pro-equity. This allows us to benchmark progress and identify which states were able to achieve more equitable vaccination in the three months following eligibility expansion.”
The researchers found vaccination rates through the end of March were substantially higher among white adults compared with Black and Hispanic adults — by about one-third — and that continuation of these unequal rates would produce one- to two-month delays to reach 50% coverage for Hispanic and Black adults, respectively. But if Hispanic and Black adults were vaccinated at a rate equal to the highest observed vaccination rate for any racial/ethnic group (with at least 200,000 population) in each state between April and July, delays to reach 50% coverage among the adult population would have been reduced by almost half.
Hispanic and Black Americans have been hospitalized at a rate 2.8 times higher than white Americans, according to the CDC. The death rate for Black adults has been twice as high as that of whites and 2.3 times higher for Hispanic and 2.4 times higher for Native American adults.
“Over and over, we’ve seen the profoundly disproportionate burden of COVID-19 on Black and Hispanic communities,” said Salomon, senior author of the study and director of Stanford’s Prevention Policy Modeling Lab. “In this analysis, we wanted to provide a detailed map of how vaccination disparities have evolved during the first six months of the campaign, but also to highlight how pro-equity strategies, including place-based prioritization of vaccination efforts, could help to close these gaps.”
In a final scenario, if states had focused efforts to double the vaccination rate among those living in the most underserved areas in their states during the first six weeks of the all-adult eligibility period, vaccine coverage disparities between Hispanic and white adults would have been eliminated by July 1, 2021 — and the coverage gap between white and Black adults would have been reduced by 76%.
“Narrowing vaccination disparities to produce better and more fairly distributed health outcomes is simple enough to say and appeals to ideas of equal access and justice,” said Goldhaber-Fiebert, one of the leaders of the SC-COSMO consortium. “But achieving this goal is as challenging as it is important. During the pandemic, many non-health disparities — from the lack of time off from work and access to transportation, to having trusted information sources — all combined to magnify disparities and the risks and adverse outcomes from infection. Therefore, solutions may require multi-sectoral actions. As a society, we can and should do better."