Will COVID-19 vaccine trials reflect those most vulnerable to the infection’s adverse effects?

Erin McCallister Senior Manager, Health Research Institute, PwC US August 20, 2020

Clinical trials have typically underrepresented racial and ethnic minorities, but calls are increasing for manufacturers of COVID-19 vaccines to turn the tide. If they are successful, they could provide a road map to increasing minority enrollment in future clinical studies.

Data continue to emerge that Black and Latino populations are bearing the brunt of adverse effects and mortality due to SARS-CoV-2 infections. A study released Aug. 17 by the Centers for Disease Control and Prevention found that racial and ethnic minorities made up an overwhelming majority of outbreak-associated workplace cases in Utah. From March to June, Hispanic and nonwhite workers accounted for 73% of workplace outbreaks, though they make up only 24% of all Utah workers.

“Systemic social inequities have resulted in the overrepresentation of Hispanic and nonwhite workers in frontline occupations where exposure to SARS-CoV-2, the virus that causes COVID-19, might be higher,” the CDC found, adding that “extra vigilance in these sectors is needed to ensure prevention and mitigation strategies are applied equitably and effectively to workers of racial and ethnic groups disproportionately affected by COVID-19.”

Minority groups have been skeptical of participating in clinical studies due to a history of exploitation in medical research, such as the Tuskegee Syphilis Study. Results from early-stage trials from the companies suggest that they’ve yet to convince members of these populations or do enough outreach to enroll them.

HRI’s analysis of available demographic data from four Phase I/II trials for COVID-19 vaccines shows that the studies were disproportionately white, with Black participants making up less than 5% of the studies and Latino individuals either not reported or constituting less than 15% of individuals enrolled.

Women also have been found to develop higher antibody responses and subsequently adverse events than men for vaccines in general, suggesting a need to enroll at least an equal number of women in vaccine studies to sufficiently assess potential adverse outcomes. Here, the early COVID-19 vaccine trials are on track, with women making up about 50% of the studies.

The FDA has urged manufacturers to ensure that the pivotal Phase III studies of the vaccines represent the range of individuals affected by the pandemic.

In an editorial in JAMA, FDA Commissioner Dr. Stephen Hahn and colleagues wrote that given the imbalance in outcomes for minority groups relative to COVID-19, it is “critical that the data derived from nonclinical and clinical studies clearly demonstrate that the vaccine is safe and effective for widespread use,” adding that study sponsors should “ensure sufficient representation of racial and ethnic minorities, older adults, and individuals with medical comorbidities in the clinical trials.”

HRI’s analysis of the clinical inclusion and exclusion criteria suggest that the companies could be on the right track, with criteria such as “participants who, in the judgment of the investigator, are at risk for acquiring COVID-19,” and participants up to age 85. While some of the Phase I trials excluded people with certain comorbidities such as hypertension, asthma and diabetes, the larger studies are also allowing these individuals, particularly if they are in “stable” condition. At least one trial is stratifying patients by age group to understand if there may be different safety or efficacy outcomes based on age.

HRI impact analysis

Once the baseline safety of an agent or vaccine has been determined, confirmatory Phase III studies often have wider inclusion criteria. However, it’s too soon to know if the removal of some barriers in the COVID-19 vaccine trials will increase minority participation in the studies.

Minority recruitment in clinical trials has traditionally been low. The National Institutes of Health hopes to use its HIV clinical trials framework as one tool to encourage minority enrollment in COVID-19 trials. HIV predominantly affects Black (42%) and Latino (22%) populations. The Phase III vaccine and therapeutic trials being managed by the NIH are using the COVID-19 Prevention Network, which includes as partners the HIV Vaccine Trials Network, the HIV Prevention Trials Network and the AIDS Clinical Trials Group.

While HIV patients are frequently excluded from clinical trials because of the potential for already impaired immune responses, at least one vaccine manufacturer has expanded its Phase III trial criteria to enroll HIV-positive individuals.

Study investigators are also partnering with churches, and a few trial sites are at historically black medical schools.

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Trine K. Tsouderos

HRI Regulatory Center Leader, PwC US

Tel: +1 (312) 241 3824

Crystal Yednak

Senior Manager, Health Research Institute, PwC US

Erin McCallister

Senior Manager, Health Research Institute, PwC US

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