Many people of color and older adults have been underrepresented in U.S.-based vaccine trials over the past decade, a new study found, emphasizing the importance of diversifying clinical trials as the country scales up its mass-vaccination campaign against COVID-19.
Black or African-American individuals (who made up 10.6% of participants in adult trials), American Indian or Alaska Native individuals (0.4%), Hispanic or Latino individuals (11.6%) and adults aged 65 and up (12.1%) were underrepresented compared to their share of the U.S. population, according to the analysis published Friday in the peer-reviewed medical journal JAMA Network Open. The gaps weren’t particularly large, the authors noted.
White individuals (77.9%) and female participants (56%), meanwhile, were overrepresented in trials. Asian (5.7%) and Hawaiian or Pacific Islander (0.2%) participants were about equally represented given their share of the population.
“When people with diverse backgrounds are not adequately represented, treatments shown to be effective in trials may not be generalizable to or effective for all populations,” the authors wrote. “Furthermore, because of previous experience with exclusion and maltreatment, vaccine hesitancy and lack of trust in the medical establishment may be more prevalent across minority groups, making inclusion even more important.”
The researchers analyzed data from 230 U.S.-based adult and pediatric clinical vaccine trials registered and reported on ClinicalTrials.gov, including 219,555 participants in total, between July 2011 and June 2020. They compared trial participants’ demographic data to U.S. census data from 2011 and 2018.
In spite of recommendations by the Food and Drug Administration, many studies didn’t comply with guidance on reporting demographic data, the authors said. Of the 230 trials, 134 reported participants’ race and 79 reported their ethnicity.
“A lack of reporting is a key finding of our study, and missing data may be important in the context of understanding health disparities, such as social determinants of health (e.g., socioeconomic barriers), implicit bias, and an increased burden of comorbidities,” they said.
The study authors went on to recommend that populations experiencing a greater burden from infectious diseases receive equitable inclusion in vaccine trials for the coronavirus and other diseases.
Many people of color in the U.S. have taken a disproportionate hit from the coronavirus. Experts say this is because of underlying structural determinants of health, such as socioeconomic status, health-coverage disparities and overrepresentation in “essential” jobs that carry higher virus-exposure risk.
U.S. Centers for Disease Control and Prevention data updated this week showed that Black Americans are 2.9 times as likely as white Americans to be hospitalized with COVID-19 and 1.9 times as likely to die from the disease. Hispanic or Latino people are 3.2 times as likely to be hospitalized and 2.3 times as likely to die; and Native American people are 3.7 times as likely to be hospitalized and 2.4 times as likely to die.
Boosting diversity in vaccine trials is important, wrote the authors of the JAMA Network Open study, because it could be associated with minority vaccination rates. “Efforts to improve inclusion may help to address vaccine hesitancy, provide education, and counter safety concerns about vaccines by ensuring equitable representation in definitive clinical trials,” they said.
Some public-health experts have suggested that COVID-19’s outsized impact on people of color means they should be overrepresented in vaccine trials. Moderna’s CEO in September said the company was slowing down its trial enrollment to ensure diversity in the participant pool.
The manufacturers of the two vaccines currently authorized in the U.S. — Pfizer
with its German partner, BioNTech
— have published the numbers of minority enrollees in their trials.
Global data from participants in Pfizer’s Phase 2 and 3 trial (about three-fourths of whom were in the U.S.) showed that 9.8% were Black, 4.4% were Asian, 0.6% were American Indian or Alaska Native, and 26.2% were Hispanic. In Moderna’s Phase 3 trial, 9.7% of participants were Black, 4.7% were Asian, 0.8% were American Indian or Alaska Native, and 20% were Hispanic.
A combination of structural access challenges, lack of awareness or information, inadequate outreach efforts, historical mistreatment of people of color by the U.S. medical establishment, and continued racism and bias in the health-care system keeps many people of color from taking part in clinical trials, said a recent analysis by the Kaiser Family Foundation.
The Pfizer and Moderna trials still underrepresented people of color rather than overrepresenting them, KFF noted, but they “have achieved greater diversity than many previous trials for other drugs.”
The manufacturers’ findings that the vaccines were similarly safe and effective for white people and people of color could mean good news for growing confidence in the vaccines, the authors added.
“[I]nformation on the diversity of participants in the clinical trials and the trials’ findings on safety and efficacy for people of color could be an important component of outreach and education campaigns and vaccination efforts that could help prevent disparities in vaccination,” the KFF report said.
As of Thursday morning, 57.7 million doses of the dual-dose COVID-19 vaccines had been administered in the U.S., with 41 million people receiving one or more doses and nearly 16.2 million people receiving two doses, according to a CDC tracker. Some 73.4 million doses had been delivered to states.
Early reports suggest that Black Americans are getting vaccinated against COVID-19 at lower rates than their white counterparts and are more likely to have to travel farther to receive the vaccines.