Covid-19: lack of diversity threatens to undermine vaccine trials, experts warn
The remarkably fast progress of two leading contenders for an effective coronavirus vaccine has raised hopes the pandemic may be speedily tamed. But some experts have warned the vaccine trials risk being undermined by a lack of diversity among their participants.
Last month, the University of Oxford reported a vaccine it is developing with AstraZeneca from a chimpanzee virus elicited a “strong immune response” in people involved in an initial trial. A separate vaccine project, overseen by the US biotech company Moderna, also saw encouraging results from an early small-scale trial.
The two research trials, striving to charge ahead of a pack of more than 140 different teams racing to find a vaccine to tackle the coronavirus pandemic, have sparked a rare burst of optimism during the crisis. But the trials are striking not only for their rapid pace but also their overwhelming whiteness.
In the Oxford trial of more than 1,000 healthy adults, 91% were white, with about 5% Asian and less than 1% black. The smaller Moderna trial saw 45 adult participants, 40 of them white and just two black volunteers.
Both of these vaccine projects are moving onto larger, more advanced phases, with Moderna enrolling 30,000 volunteers for its latest stage and Oxford holding a phase three trial in India. But the lack of diversity in the early trials risks blind spots in developing a vaccine for a condition that has disproportionately hospitalized and killed people of color in the UK and US, according to Oluwadamilola Fayanju, a surgeon and researcher at Duke University.
“It’s disappointing because … they are countries where there are known huge disparities along racial lines,” she said.
“Diversity is important to ensure pockets of people don’t have adverse side-effects. People of color disproportionately have co-morbidities such as hypertension and diabetes and you need to know how these things interact with any vaccine.
“I recognize getting this vaccine is an urgent priority and we all want it quickly but we can’t cut corners because something may be missed. They are causing more difficulties for themselves by not including diversity from the beginning.”
Research has shown that people from different racial backgrounds can respond differently to drugs and therapies. Other factors such as age – people’s immune response lessens as they get older – are also important.
Despite US government encouragement to hold diverse processes, however, American drug trials are often white-dominated. Black people make up an average of 5% of clinical trials, less than half of their overall population share in the US. Hispanics make up around 18% of the US population but just 1% of trial participants, on average.
People of color are regularly hindered by poorer-quality health insurance that doesn’t cover the time and expense of taking part in a drug trial, as well as issues of trust stemming from a legacy of unethical and forced drug experiments. “There is a history there and now they are being bypassed again,” said Fayanju.
Marjorie Speers, executive director of Clinical Research Pathways, a charity that promotes ethical research, said it is “essential” that vaccine trials involve sufficient numbers of black and Latino people to help curb a disease that has surged through minority communities.
“If we fail to enroll minorities, then we create a new health disparity because minorities will continue to suffer from the virus if they aren’t protected by a vaccine,” she said.
But Speers added it is often complicated for drug companies to do this as they have to actively reach out and rebuild frayed relationships with certain groups. “Some minorities do not trust researchers,” she said. “We have a long and painful history of research abuses in the black and Latino populations.”
Drug companies could employ more black and Latino staff to help this effort, Speers suggested. Researchers and medical journals, meanwhile, could ensure “radical transparency” by explaining attempts to create a diverse field of participants, according to Fayanju.
Even if an effective vaccine is found that is suitable for all, however, it remains an open question as to whether the US will be able to swiftly distribute it to the millions of people of color who make up a large segment of frontline workers most exposed to the virus.
Six months after the outbreak began in America, testing and contract tracing is still occurring at lower levels than experts recommend, while lingering shortages of protective equipment bedevil some healthcare staff.
“Right across the board there are inequalities in who is getting support in this pandemic,” said Rhea Boyd, a pediatrician and child and community health advocate. “Health insurance tiers people, which racially stratifies the care, while the allocation of resources is deeply rooted in racial disparities. Right now, we are making decisions based on legacies of racism.”