Prioritizing Diversity in Vaccine Clinical Trials: 5 Strategies for Success
5 Minute Read
Clinical trial diversity is essential to ensure novel therapeutics are effective and safe for the populations they are intended to treat. Vaccines are no exception, as they can differentially affect groups reflecting variation in environmental exposure and underlying experiences. However, diversity has historically been an issue in vaccine studies. An analysis of 230 U.S.-based vaccine trials from July 2011 through June 2020 involving a total of nearly 220,000 participants found that racial and ethnic minorities and people aged 65 and older were not being equitably represented.1 As the primary point of contact with patient populations, clinical research sites play a critical role in overcoming potential barriers to vaccine trial participation to optimize diversity.
According to a study conducted by the VACCELERATE consortium, the potential barriers to participation in vaccine trials among underrepresented groups include:2
- Lack of trust in vaccines and healthcare systems
- Low levels of health literacy
- Language barriers, particularly affecting ethnic minorities, refugees, migrants, and immigrants
- Lack of healthcare provider recommendations
- Geographic and socioeconomic barriers to accessing healthcare
In this blog, we explore 5 strategies that sponsors and sites can leverage to eliminate participation barriers, providing actionable steps for prioritizing and promoting diversity in vaccine clinical trials.
1. Building trust
Low levels of trust in vaccines and healthcare systems are a significant barrier to clinical trial participation, especially among underrepresented groups. A recent survey of U.S. adults found declining confidence in vaccines and increasing willingness to accept misinformation about vaccines in the wake of the COVID-19 pandemic. Research has also shown that there is a racial gap in trust in the healthcare system, and perceptions of unfair treatment in healthcare due to historical unethical medical practices, inequities in resource availability, and racial discrimination are increasing.3
To overcome these barriers, sites may consider engaging with established community and religious leaders or healthcare providers who are already trusted by these populations. Partnering with these known quantities to host informational sessions on the value of vaccines and clinical trials is a good first step in establishing standing within the community and opening minds to the opportunities of study participation.
Patient and public involvement (PPI) is a strategy where members of the public, particularly those from underserved or underrepresented groups, are invited to participate in the design and implementation of clinical trials. This strategy not only ensures that studies are more relevant and accessible to the communities they aim to serve, but also creates a sense of ownership among community members for the success of those studies. PPI can also help to identify potential barriers to participation and develop solutions that are grounded in the real world experiences of the target population.
Keep in mind that trust building and PPI are not static, one-and-done activities. After successful study enrollment, seeking feedback from participants about their experiences can provide sponsors and sites with valuable insights into how future trials can be more inclusive and accessible.
2. Enhancing health literacy
Low health literacy is a common barrier to trial participation. In a study analyzing the association between health literacy and attitude toward vaccines, higher levels of health literacy were associated with lower vaccine hesitancy and greater confidence in healthcare systems.4 Other research has found that lower levels of education, Black race, and Hispanic ethnicity were associated with lower health literacy, which in turn was associated with lower vaccine confidence.5
To improve understanding and acceptance, sites should provide education about the purpose of vaccines, the clinical trial process, and what participation entails. This can be done through workshops, informational brochures, and one-on-one consultations. Health literacy efforts should be ongoing, not just during the recruitment phase, to ensure participants fully comprehend and are comfortable with the trial process.
3. Speaking the patient language and applying cultural intelligence
Effective communication is vital for recruiting diverse participants. Addressing vaccine hesitancy among underserved and underrepresented requires both empathy and evidence-based, patient-centered information. This involves not only translating materials into multiple languages but also adapting them to be culturally relevant and sensitive. This requires consideration of race, ethnicity, nationality, and religious affiliations, all of which may impact willingness to receive vaccines.6 Researchers should use various communication channels, such as community radio, social media, and local newspapers, to reach different demographics. Simplifying medical jargon and providing clear explanations about the purpose, procedures, and potential risks and benefits of a vaccine clinical trial will make it more accessible.
Keep in mind that representation matters, not only among trial participants but also within the research teams and clinical trial site staff. Involving researchers, clinicians, and study personnel from diverse backgrounds can help bridge cultural gaps and make participants feel more understood and respected. It also fosters a more inclusive environment that encourages diverse participation.
4. Eliminating access issues
People of color face an array of access-related barriers to participating in clinical trials. For example, fewer studies are available through under-resourced hospital systems where racial and ethnic minorities are more likely to receive care.7 Other access challenges include prohibitive distance to study sites for people with limited transportation options, lack of flexibility in work or caregiving responsibilities, and limited access to technology may also increase barriers to participation.
To address these issues, offer transportation vouchers, flexible scheduling, or even mobile clinics that bring the vaccine trial to the community. Providing compensation for time and travel can also make participation more feasible for those with limited financial resources.
5. Partnering with sites that have proven diversity
As with any other clinical trial, site selection is a critical determinant of success in vaccines studies. Understanding the demographics of the patient population within a site database helps in estimating the potential diversity of a planned clinical trial.
Key Takeaway
Diversity and access to critical trials is important for ensuring generalizability and efficacy across different population groups. Targeted interventions and communication strategies at the site level can help break down barriers to participation and create more inclusive vaccine trials that reflect the diversity of the global population.
To sustain that diversity, it is necessary to continuously monitor recruitment practices and participant demographics. Sites should regularly collect and analyze data on who is participating and who is being left out. This information can guide adjustments in recruitment strategies and help ensure that efforts to increase diversity are effective and sustainable.
To learn more about how Alliance Clinical can accelerate your vaccine program, contact us today.
1Flore LE, et al. Assessment of the Inclusion of Racial/Ethnic Minority, Female, and Older Individuals in Vaccine Clinical Trials. JAMA Netw Open. 2021;4(2):e2037640.
2Poulimeneas D, et al. The Challenges of Vaccine Trial Participation among Underserved and Hard-to-Reach Communities: An Internal Expert Consultation of the VACCELERATE Consortium. Vaccines. 2023;11(12):1784.
3KFF. The Undefeated Survey on Race and Health, October 13, 2020. Available at https://www.kff.org/report-section/kff-the-undefeated-survey-on-race-and-health-main-findings/#HealthCareSystem.
4 Khoury G, et al. Health literacy and health care system confidence as determinants of attitudes to vaccines in France: Representative cross-sectional study. JMIR Public Health Surveill. 2024;10:e45837.
5 Hurstak E, et al. The mediating effect of health literacy on COVID-19 vaccine confidence among a diverse sample of urban adults in Boston and Chicago. 2023;41(15):2562-2571.
6 Richard-Eaglin A, McFarland ML. Applying cultural intelligence to improve vaccine hesitancy among black, indigenous, and people of color. Nurs Clin North Am. 2022;57(3):421-431.
7Hamel LM, et al. Barriers to clinical trial enrollment in racial and ethnic minority patients with cancer. Cancer Control. 2016 ;23(4):327-337.
