On this page
- What was actually trialled
- Why that evidence does not transfer
- Post-exertional malaise changes everything
- The natural history problem
- Other post-viral syndromes
- What is being offered
- The immune reset claim
- What does have support
- Questions worth asking
- Frequently asked questions
- Requesting a medical evaluation
Severe acute COVID-19 attracted one of the largest bursts of cell therapy research in the field’s history. Long COVID attracted almost none. Stem cell therapy for long COVID and post-viral recovery is sold on the first body of evidence while treating people who belong to the second, and the two are not connected.
What was actually trialled
Cord-derived cells were studied in severe COVID-19 — Treatment of severe COVID-19 with human umbilical cord mesenchymal stem cells.
A double-blind randomised controlled trial examined cell therapy in COVID-19 acute respiratory distress syndrome — Mesenchymal stromal cell therapy for COVID-19 acute respiratory distress syndrome: a double-blind randomised controlled trial.
Vesicle preparations were tested too — Human placental mesenchymal stromal cell-derived small extracellular vesicles as a treatment for severe COVID-19: A double-blind randomized controlled clinical trial and Bone Marrow Mesenchymal Stem Cell-Derived Extracellular Vesicle Infusion for the Treatment of Respiratory Failure From COVID-19: A Randomized, Placebo-Controlled Dosing Clinical Trial.
Read the populations. Severe disease. Acute respiratory distress. Respiratory failure. These are intensive care patients, and the endpoints were survival and time on a ventilator.
Why that evidence does not transfer
Severe acute COVID involves a violent inflammatory response damaging the lungs over days. Suppressing that inflammation in an intensive care unit is a coherent target, and it is what these trials tested.
Long COVID is a persistent, fluctuating, multi-system illness in people who are no longer acutely infected, with fatigue, cognitive symptoms, exercise intolerance and autonomic disturbance among its features. Its mechanisms remain contested.
Nothing in the acute trials speaks to that. The trials also measured inflammatory markers — Impact of mesenchymal stromal/stem cell infusions on circulating inflammatory biomarkers in COVID-19 patients: analysis of a phase I-IIa trial — in patients whose markers were dramatically raised, which is not the case in most people with long COVID.
Post-exertional malaise changes everything
A core feature for many people with long COVID, and for those with ME/CFS, is that exertion makes them worse — often a day or two later, and often out of proportion to the effort.
That has a direct consequence for treatment travel. Long-haul flights, time-zone shifts, hospital appointments and an unfamiliar climate are exactly the kind of cumulative exertion that provokes a crash.
Someone may return home worse than they left, and attribute it to the illness rather than the trip. This deserves stating plainly before anyone books anything. Chronic fatigue syndrome covers the same issue.
The natural history problem
A substantial proportion of people with long COVID improve over months to years without specific treatment. That improvement is gradual and uneven.
Anyone treated during that period will improve afterwards, and will reasonably credit the treatment. With no control group, there is no way to separate the two.
The condition also relapses and remits. A good fortnight after treatment is not a result.
Other post-viral syndromes
Persistent illness after infection is not new. It has been described after glandular fever, Ross River virus, Q fever, SARS and others, and it has been recognised for over a century.
None of those has a cell therapy trial either. The COVID research boom was driven by the acute pandemic emergency and the funding that came with it, and it did not extend to the post-viral illness that followed.
That is a gap in the research, and a gap in the research is not a licence to fill it commercially.
What is being offered
Intravenous infusions, often packaged with vitamin drips, ozone therapy, hyperbaric oxygen or exosome preparations, marketed for immune reset or recovery.
Exosome products in particular are heavily promoted here and are the least evidenced thing on this site — exosome therapy.
The prices are substantial, the patients are often unable to work, and that combination deserves to be named directly rather than left implicit.
The immune reset claim
The phrase most often used to sell this is immune reset or immune reboot, and it has no defined meaning. No test is offered before to establish that the immune system needs resetting, and none afterwards to show that it was.
Some people with long COVID do have measurable immune abnormalities, and research into those is active and legitimate. Finding an abnormality in a research cohort is not the same as having a treatment that corrects it, still less one that makes people better.
Where markers have been measured in cell therapy trials, it was in acutely unwell patients with dramatically raised inflammation, and a change in a blood marker is not itself a clinical benefit.
If a clinic uses the phrase, asking what will be measured and what number would count as a reset is a reasonable question. There is usually no answer.
What does have support
Careful activity management, including pacing for those with post-exertional symptoms, where pushing through reliably makes things worse.
Treatment of identifiable components — orthostatic intolerance, sleep disturbance, mast cell symptoms, deconditioning where it genuinely applies rather than as a default assumption.
Specialist post-COVID services exist in many countries and are free at the point of use in several. That is worth exhausting first.
Questions worth asking
- Which trial was run in long COVID rather than in acute severe COVID?
- Do I have post-exertional symptoms, and what does that mean for travelling?
- What happens if I deteriorate while abroad?
- What is the refund position if I cannot travel or cannot complete treatment?
The limits of current evidence covers this pattern across the field, and international patients sets out what travel here involves.
Frequently asked questions
There were lots of COVID trials. Do they apply to long COVID?
No. They were run in intensive care patients with severe acute disease and respiratory failure, measuring survival and ventilator time.
Is there a long COVID trial?
No controlled trial of cell therapy in long COVID or post-viral fatigue has been published.
Why might travelling make me worse?
If you have post-exertional malaise, cumulative exertion from flights, appointments and time-zone shifts is exactly what provokes a crash.
People say it helped them. Why doubt it?
A substantial proportion of people improve over months anyway, and the condition relapses and remits. Without a control group the two cannot be separated.
What about other post-viral illness?
Persistent illness after infection has been described for over a century and has no cell therapy trials either.
Are exosomes worth trying instead?
They are promoted heavily for this and have less evidence than cells, not more.
Requesting a medical evaluation
Nothing on this page establishes whether any treatment is appropriate for you. That needs your history, your imaging and your current medications read by a clinician. If you would like that review, send your records and we will tell you honestly whether there is anything worth discussing — including when the answer is no.
This page is general information, not medical advice, and does not create a doctor–patient relationship. Regenerative treatments discussed here are in most cases investigational. Discuss any treatment with a clinician who knows your history.