Minorities Are Underrepresented in Vaccine Clinical Trials

Vaccine clinical trials have fallen short of diversity guidelines during the past decade, with minority groups underrepresented and key data missing in many trials, a new study found.

Black, American Indian, Hispanic and older adults have been underrepresented in vaccine clinical trials during the past decade, according to a new analysis.

The cross-sectional study, published in JAMA Network Open, included 230 clinical trials based in the United States and registered on ClinicalTrials.com between July 1, 2011 and June 30, 2020. The trials studied involved 219,555 participants.

“I believe there are three big takeaways from our research,” first author Laura Flores, BA, a PhD candidate at the University of Nebraska Medical Center, told Contagion®. “Our study highlighted a decade's worth of disparities—with Hispanic or Latino, Black or African American, American Indian/Alaska Native and older populations often left out of vaccine clinical trial research.

“Additionally, the lack of race and ethnicity reporting in ClinicalTrials.gov was a startling finding. With missing ethnicity data in over 60% percent of trials, and missing race data in 40% of trials, it is difficult to assess the true representation among clinical trials participants.

“Female adults were overrepresented overall and within all phases of vaccine clinical trial research over the last decade.”

Age and sex of participants were reported for every trial, race was reported for 134 (58.3%) and ethnicity was reported for 79 (34.3%).

“I believe the lack of data reporting was a big shock to the entire team,” Flores said. “We can’t begin to solve inequalities in clinical trial research without the whole picture.”

Compared with U.S. census data, white Americans were overrepresented in vaccine clinical trials, accounting for 77.9% of adult participants, while those underrepresented included Black or African American individuals at 10.6%, American Indian or Alaska Native individuals 0.4% and Hispanic of Latino individuals at 11.6%. Asian individuals were equally represented to the US census data at 5.7%.

Adult trials included more female participants (56%). Those age 65 and older were underrepresented (12.1%).

Pediatric trials also showed a underrepresentation among Black participants (10.1%) and Hispanic participants (22.5%)

“Our study highlighted some good news in that we are close to reflecting the racial makeup of the US population in vaccine clinical trials,” Flores said. “With race, the gaps we identified are much smaller than in other research areas, like oncology clinical trials, and this signals we might be on the right track. That being said, we believe it is important to note that small inequities are still important inequities. We are doing a genuine disservice to these populations by not reaching out, and not keeping records, and not including them in trials that might benefit them.”

The NIH Revitalization Act of 1993 directed the National Institutes of Health to establish guidelines for including women and minorities in clinical trials. In 2017, the NIH amended the policies for reporting data, and the US Food and Drug Administration (FDA) issued a consumer update stressing the importance of diversity in clinical trials.

Missing data on race and ethnicity deprives studies of important context for understanding health disparities such as socioeconomic barriers, implicit bias and increased burden of comorbidities.

Flores said she hopes the study leads to better demographic reporting by investigators.

“Enrolling the right populations and in particular the most impacted populations in clinical trials is not a luxury but a necessity,” author Carlos del Rio, MD, of Emory University School of Medicine told Contagion®. “I am hopeful that the National Academy of Science Engineering and Medicine Committee will come up with good recommendations that will help improve the representation of diverse populations in clinical trials and research.”

Author Michele Andrasik. PhD EdM, of Fred Hutchinson Cancer Research Center, emphasized the importance of building trustworthy relationships with communities to ensure good public health for all.

“We need concerted efforts to ensure the inclusion of diverse participants in clinical trials,” Andrasik told Contagion®. “This will require going beyond guidelines and potentially implementing sample requirements going forward. The same is true for the collection of race and ethnicity data. The large incidence of missing data is unacceptable.”

The coronavirus disease 2019 (COVID-19) pandemic has brought additional challenges to clinical trials. Last year, the FDA issued guidelines for conducting clinical trials during the pandemic, acknowledging challenges brought by quarantines, site closures, travel limitations and interruptions to the supply chain and urging measures such as increased safety monitoring, shifting to telemedicine platforms and including explanation for any missing data due to disruptions.