"I'm concerned that individuals purchasing these supposed 'therapies' for COVID-19 will be scammed," says Turner, an associate professor at the University of Minnesota Center for Bioethics. "I'm also worried that they'll be injured as a result of being given products that haven't been adequately tested, or that they'll forgo measures like social distancing because they've paid for a product that they think will protect them from being infected or getting sick."

Many stem cell clinics have a history of selling unproven and unlicensed interventions for injuries and illnesses ranging from Alzheimer disease to pulmonary disorders to spinal cord injuries. Since the COVID-19 pandemic began, some have added claims about "immune-boosting" therapies for treating COVID-19 and acute respiratory distress syndrome (ARDS) caused by infection with SARS CoV-2. These companies advertise stem cell interventions and exosome products derived from such sources as umbilical cords and amniotic fluid. Turner says uncritical news media accounts have compounded some of these claims by reporting on preliminary evidence and case studies.

Yet rigorous clinical trials on these stem cell products have not yet been done. "Randomized controlled trials are needed to establish whether particular stem cell products are safe and efficacious in the treatment of COVID-19-related ARDS," he explains.

Turner has studied the US direct-to-consumer marketplace for stem cell clinics for nearly a decade. "These businesses have a long history of claiming to treat diseases and injuries for which evidence-based therapies do not yet exist," he says. To find out what these businesses were promoting, he did Google searches on a variety of terms related to stem cell treatments, COVID-19, and ARDS. He also searched YouTube for promotional videos made by these clinics.

"I found more examples of businesses peddling stem cell products for COVID-19 than I had space to describe in detail," he notes. "I wasn't surprised at how quickly some of these companies began making these claims. For them, the COVID-19 pandemic is an opportunity to generate a new revenue stream."

In the paper, Turner also discusses the role of medical organizations, noting that while most are doing a good job of criticizing deceptive advertising, some have been promoting these interventions despite the lack of scientific evidence supporting their use.

"I want members of the public to know that some companies are trying to take advantage of them by selling supposed treatments that aren't backed by credible evidence," Turner concludes. "I'm also hoping that this paper will catch the attention of regulatory bodies like the Food and Drug Administration (FDA) and the Federal Trade Commission (FTC), as well as state medical boards and state attorney general offices. The FDA and FTC have issued letters to some businesses, but additional regulatory action is needed."