U.S. vaccine trials over the past decade have not included enough seniors and Hispanic and Black adults, and show a failure to report needed demographic details, according to a study published in JAMA Network Open Friday looking at a large sample of trials.

Why it matters: By not capturing a representative sample of Americans, vaccine trials cannot fully demonstrate the safety and effectiveness for all people and miss out on an opportunity to build trust within underrepresented communities — something vitally important in the COVID-19 pandemic, two experts tell Axios.

• "It makes it harder to ensure that our drugs and medicines are going to work for all people," says Namandjé Bumpus, director of the department of pharmacology and molecular sciences at Johns Hopkins University School of Medicine.
• "There are certain genetic variants, particularly involved in drug processing, that seem to very closely track with geography and ancestral origin and can be more prevalent in certain groups than others," says Bumpus, who was not part of the study.
• Study co-author Steven Pergam says the "downstream effect" of inclusivity is important for building trust in communities for vaccines, particularly "when you look at the data about the clinical trial and you see people like yourself included, and you show the safety and efficacy in those groups."

The state of play: Despite efforts by the NIH and FDA to require more trials to report age, sex, race and ethnicity, most do not comply completely. Examining data from 230 vaccine trials between mid-2011 to mid-2020 with 219,555 participants, the JAMA study found all reported age and sex, but only 58% reported race and 34% ethnicity.

• "That's a big issue. The reporting is not happening, despite the policies," Bumpus says.
• While the study paints an incomplete picture partly because of that underreporting, "what we're seeing here is a microcosm for what's going on more broadly with both vaccines and drugs," she says. These are reproducible overall trends in trials, she adds.
• "We need more outreach and education" to combat the misinformation and long-term distrust that people of color have in the medical community overall and in vaccines specifically, Bumpus says.

Besides the discrepancy in underreporting by most trials, Pergam, associate professor in the Vaccine and Infectious Disease Division at Fred Hutchinson Cancer Research Center, says an examination of adult trials found:

• Hispanic (12%) and Black (11%) adults, as well as seniors (12%), were not represented equitably, while white people (78%) and women (56%) tended to be overrepresented.
• The "definitive" phase three for clinical trials — testing large numbers of the population with the goal of gaining FDA approval — actually had a less-diverse population than the initial trial phases.

Between the lines: Finding less inclusiveness in phase three trials is concerning, and may be due to their focus on "ease and speed" that tends to preclude underrepresented communities who are not as established in the medical system, Pergam says.

• "The problem is when you aim for speed, you often miss these groups because it does take time and effort ... and you need to prioritize this."
• COVID-19 trials can serve as a model, Pergam says. "As an example, the Moderna trial did slow down enrollment to make sure they had adequate enrollment of underrepresented minorities, which I think was really key. They put time, they put money, they put people in these groups. They met with community groups ahead of time."

One positive takeaway is that it "debunks this myth that's so prominent right now, that [Black and Hispanic Americans] don't enroll in clinical trials. Clearly we do," Bumpus says. "This [study] shows we're underrepresented but it also shows there clearly is a willingness. We are there. So there are things that can be done to improve that."

The bottom line: Federal agencies and science publications need to get serious about putting some teeth into their policies for studies to report demographics, they said. And trial organizers need to make a concerted effort to reach out to underrepresented communities and set specific diversity enrollment targets.

Check out: Axios' Get Smart videos on vaccines.

Go deeper: The cost of racial disparities in clinical trials