Dozens of health clinics across the country are selling unauthorized stem cell treatments purported to prevent and treat the side effects of COVID-19.

Thirty-eight businesses serving around 60 clinics in the United States, Mexico, and elsewhere are providing stem cell treatments and exosome therapies, most of which also claim to treat Long Covid, according to a new paper in the journal Stem Cell Reports.

Long Covid is a term for the long-term effects of a COVID-19 infection with symptoms including tiredness, fevers, shortness of breath, coughing and chest pain, brain fog, dizziness, anxiety and depression, and digestive symptoms, according to the CDC.

These treatments have not been approved by the Food and Drug Administration (FDA) or other national regulators and "do not appear to be supported by convincing safety and efficacy data," the authors wrote in the paper.

Stem cell treatments work by inserting stem cells into a patient, where they will grow and adapt to the chosen tissue, repairing damage. These treatments are usually very specific, and the stem cells will have been prepared and possibly genetically modified to best perform in the tissue or organ that requires healing. Exosome therapy uses exosomes, which are tiny particles found within stem cells, to deliver proteins and other molecules to areas that need treatment.

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Stock image of stem cells. Unregulated stem cell treatments for Long Covid and other COVID-19 symptoms are being sold by clinics in the U.S. and beyond.

However, these types of treatment must undergo rigorous investigation before being approved by a body such as the FDA, which none of the alleged Long Covid treatments have. Additionally, injecting undifferentiated pluripotent stem cells into a patient is unsafe, as it could cause tumors to form. In the past, unproven stem cell treatments have led to patients being blinded, infected with dangerous pathogens, or even paralyzed.

These treatments can still be advertised legally without FDA approval, however.

"People who are going online and looking for treatments, especially for Long COVID, need to be alert to marketing misrepresentations that minimize risks and make misleading claims about the likelihood of benefits," Leigh Turner, a bioethics professor at the University of California, Irvine, and lead author of the paper, said in a statement.

"It's understandable given the considerable number of individuals that continue to experience illness following the acute infection phase of COVID-19. It's also disturbing because the people paying for these products are not being provided access to evidence-based treatments."

The stem cell treatments claiming to treat Long Covid have not been approved or even proven to actually do what they say on the tin.

"The patients being targeted by such marketing claims are particularly vulnerable," Turner said. "They're suffering, and in some cases, they've been suffering for a long time, making them highly susceptible to misleading marketing representations and persuasive marketing pitches. And while some of these patients might have access to reputable Long COVID clinics working with best available evidence, that access doesn't mean they're getting the therapeutic relief they are seeking."

Twenty-four of the 60 clinics providing these treatments are U.S.-based, while a further 22 are in Mexico, and several others are found across the Cayman Islands, Guatemala, Malaysia, Panama, Philippines, Poland, Spain, Thailand, Ukraine and the United Arab Emirates, the paper reveals

Before these clinics claimed to treat Long Covid, many of them said they could treat acute COVID-19 symptoms during the spring of 2020 or even prevent the infection altogether.

"It's a shape-shifting marketplace," Turner said. "Some businesses stopped marketing after receiving warning letters from the Food and Drug Administration or the Federal Trade Commission. Other companies and clinics have entered the marketplace and in some cases apparently managed to avoid detection by regulatory bodies and law enforcement agencies."

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Stock image of COVID-19 virus particles. Unauthorized stem cell treatments can be dangerous for patients.

Not only are these treatments potentially useless or even harmful, but they are also extortionate: "The least expensive product cost $2,950, the most expensive was $25,000, and the average listed cost for patients was $11,322," the authors wrote in the paper.

"In addition to the possibility of being harmed by these products, there's also the possibility of being scammed out of thousands of dollars," Turner said.

The authors hope that their findings will help stem cell therapies be ruled as requiring FDA approval before they can reach people, as currently, marketers of unproven stem cell-based interventions can make exaggerated claims about the effects of their products.

"There was a robust response from regulatory bodies and law enforcement agencies to companies making unsubstantiated claims in the early days of the pandemic," Turner said. "I hope this study encourages regulatory bodies and law enforcement agencies in these countries to continue to act in response to these businesses, which are putting patients at risk of physical injuries and financial losses by using misleading marketing representations to sell unapproved and unproven products."

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