Why Diversity Matters In COVID-19 Vaccine Trials

will COVID-19 vaccine trials reflect diversity?

 Ellen Lindner / Verywell

Key Takeaways

  • To date, the demographic breakdown of many COVID-19 vaccine trials shows a lack of diversity among participants.
  • Representation of racial minorities is important to ensure a safe and effective vaccine for everyone.
  • Ensuring that clinical trials are both trustworthy and accessible for typically underrepresented communities helps the medical community better treat those communities.

Drug manufacturers are performing clinical trials at an unprecedented speed as they race to deliver safe and effective vaccines for COVID-19. However, these trials may not reflect the populations in greatest need.

When vaccine frontrunners Moderna and AstraZeneca released their Phase 1 safety trial results in mid-July 2020, results revealed a significant observation: Around 90% of participants in both studies were White.,  Yet minorities are 1.2 to 4.1 times more likely to be hospitalized with COVID-19, according to data from the Centers for Disease Control and Prevention (CDC).

“We need diversity in clinical trials so that we have an understanding of how safe and effective treatments are in different populations, especially if those populations will consume the medication/vaccine in high numbers,” Brandy Starks, MBA, MSHS, a clinical researcher and founder and CEO of Clinical Trials in Color Foundation, tells Verywell.  

Race and Disease Risk in Clinical Trials

"Generally, race is a social concept," Starks says. "However, when we look at race in clinical trials, we’re looking at a multitude of shared factors in an ethnic group and how medications work for people in that particular group."

These factors include:

  • Diet
  • Environment 
  • Geographic location
  • Genetics 
  • Presence of multiple health conditions (comorbidities)

Research shows the effect these factors can have. For example, an asthma treatment study in 2018 found that Black and Puerto Rican children have genetic traits that make albuterol (one of the first-line treatments for asthma) less effective than it is in White and Mexican children. The study’s researchers concluded that knowledge of the most effective asthma treatment for minorities remains limited because only a few other asthma studies had prioritized diversity.

“Blacks represent 13% of the population but less than 5% of participants in clinical trials. Latinos—who represent 18% of the population—represent less than 1% of clinical trial participants,” epidemiologist Marjorie A. Speers, PhD, executive director of Clinical Research Pathways, tells Verywell. 

These statistics on underrepresentation raise concerns about the outcome when medications for conditions that disproportionately affect racial minorities—including heart disease, asthma, diabetes, and now COVID-19—have not been adequately tested in these populations.

Why Minorities Aren’t Recruited 

Several factors contribute to the underrepresentation of racial minorities in all kinds of clinical trials, ranging from historically poor experiences to a lack of communication from healthcare providers.

Mistrust Towards Trials

Starks’ organization, Clinical Trials in Color, uses social networking and referrals to encourage people of color to participate in clinical trials. However, discussing clinical trials with some populations inevitably resurrects memories of the country's dark history of unethical clinical research. 

“When I speak with communities of color about participating in clinical trials, the Tuskegee Syphilis study and Henrietta Lacks always come up, and that should be expected,” Starks says. "We serve as an independent advocate on behalf of the participant and can intervene with the study team if issues or questions arise, especially around informed consent and adverse events."

To help build trust between clinical researchers and minority communities, Clinical Trials in Color has been offering one-on-one advocacy support during COVID-19 clinical trials. Starks says the organization educates major pharmaceutical companies on how they can build trust through community health investments and make participation easier for minority populations.

Who Was Henrietta Lacks?

In 1951, a Black woman named Henrietta Lacks was diagnosed with terminal cervical cancer at Johns Hopkins Hospital (JHH). She underwent treatment at JHH, where a doctor named George Gey took a sample of her cancer cells without her knowledge.

Unlike other cervical cancer cell samples that Gey had seen, Lacks’ cells stayed alive once removed from her body. They also kept growing. Her cells—codenamed HeLa—became a pivotal tool in a wide range of medical research and were instrumental in the development of the polio vaccine.

However, Gey’s decision to obtain and conduct experiments on Lack’s cells without her consent raised controversy and ethical concerns. 

What Was the Tuskegee Experiment?

In 1932, the U.S. Public Health Service conducted a “syphilis study” on 600 Black men at the Tuskegee Institute, 399 with syphilis and 201 without. At the time, there were no proven treatments for syphilis. The men were not paid for their participation. Instead, they were offered free medical exams and free meals.

According to the CDC, the men had periodic physicals and were told they were being treated for "bad blood." There is no evidence researchers informed them of the study or its real purpose, and the men did not have all the information necessary to provide informed consent.

The study lasted for 40 years. When penicillin became a standard treatment for syphilis in 1942, the researchers withheld the treatment from the subjects. This ultimately led to public outcry and a class-action lawsuit on behalf of the subjects and their families. Study participants and their families reached a $10 million settlement in 1974.

Lack of Awareness

Racial minorities are often not involved in clinical trials because they aren't given the opportunity to participate in the first place. 

For people who have exhausted all available options for treating a disease such as cancer, clinical trials can be the gateway to new treatments. However, information about clinical trials can be hard to find if your healthcare provider doesn't let you know about it.

“I’ve received care from large academic medical centers conducting hundreds of research studies, but I’ve never been asked to participate in a clinical trial," Starks says. "Could it be this perception that as a Black woman, I would not be interested? It’s frustrating and leaves me feeling that I’m missing out on the latest and most innovative treatment options."

Retention and Accessibility Issues

Recruiting minorities to be participants is one challenge, but getting them to remain in the trial is another. “Recruitment is an ongoing process,” Speers says. “[Clinical research sites] have to develop and maintain relationships with communities of color before, during, and after trials.”

Speers adds that child care or transportation costs might have to be covered to ensure participants can stay in the trial.

Brandy Starks, CEO, Clinical Trials in Color Foundation

Researchers have been discussing the lack of diversity in clinical trials for decades with very little action or coordination to implement solutions.

— Brandy Starks, CEO, Clinical Trials in Color Foundation

The Pharmaceutical Industry's Response

In May, the Food and Drug Administration (FDA) released guidelines calling for minorities to be adequately represented in drug trials related to COVID-19. During a U.S. congressional hearing on July 21, four of the five major pharmaceutical companies in attendance pledged to have more inclusive clinical trials.

Here’s a breakdown of what we know about how these four companies plan to increase the diversity of their COVID-19 vaccine trials and what's been done so far within later phases.    


In a press release issued on July 27, Moderna shared that during its Phase 3 (final) trials, they would work with approximately 100 clinical research sites to ensure “that the participants are representative of the communities at highest risk for COVID-19 and of our diverse society.”

Moderna announced that 37% of the study population (11,000 participants) in its phase 3 trials are from communities of color. This includes about 20% of study participants who identify as Hispanic or Latinx and about 10% of participants who identify as Black.

The Moderna vaccine was authorized in December for emergency use in the United States.

Johnson & Johnson 

In a written testimony from the July 21 hearing, Johnson & Johnson stated, “To achieve recruitment of people from highly affected communities, we plan to implement a focused digital and community outreach plan.”

The company added it had partnered with Johns Hopkins University and congressional leaders to collect and analyze demographic data in areas affected by COVID-19.

Johnson & Johnson started Phase 3 trials in September.


Pfizer's testimony says the company developed a dashboard with demographic data from Johns Hopkins University and the U.S. Census Bureau to identify areas of opportunity for the placement of studies in communities of color.

Pfizer is currently working on both Phase 2 and Phase 3 clinical trials, and its vaccine is authorized for emergency use in the United States.

Pfizer announced that within its Phase 3 trials, 26% of participants identify as Hispanic/Latinx, 10% as Black, 5% as Asian, and 1% as Native American.


During the congressional hearing, AstraZeneca said that “ensuring diversity in these [Phase 2 and 3 trials] trials, including in terms of race, ethnicity, gender, age, and other factors, is a priority in our efforts.

Verywell Health reached out to AstraZeneca for additional details on its diversity initiatives but did not receive a response in time for publication.

Preliminary data from AstraZeneca's Phase 2 and 3 trials published in December showed that 91% of the study population in its U.K.-based trials and almost 67% of the population in its Brazil-based trials identify as White. In the trials in Brazil (10,000 participants), about 11% of participants identify as Black, between 2% and 6% as Asian, and almost 20% as mixed race.

What Should Drug Companies Be Doing?

There's plenty of skepticism about whether or not the stated initiatives from pharmaceutical companies will be effective.

“Researchers have been discussing the lack of diversity in clinical trials for decades with very little action or coordination to implement solutions," Starks says.

Speers says that “inclusion starts at the design of the trial.” She proposes a few strategies to increase diversity in clinical trials, including: 

  • Employing Black and Latinx physicians as expert consultants
  • Choosing clinical research sites that can specifically recruit minorities
  • Recruiting minority clinical investigators to conduct the trials
  • Establishing patient advisory boards to guide researchers and companies on the needs and interests of minorities

Speers’ organization, Clinical Research Pathways, works with Morehouse School of Medicine to train and mentor minority physicians as clinical investigators. She says that these clinical investigators are already actively engaged in COVID-19 clinical trials.

“Urgency in developing a vaccine is no excuse to create another health disparity between Whites and minorities,” Speers says. “It’s not acceptable to use a wait-and-see approach.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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