Do stem cells have a role in the treatment of COVID-19?

(Read this post to learn about evidence-based medicine concepts relevant to scientific findings on COVID-19.)

 

KEY MESSAGE
It is not possible yet to say whether stem cells are effective or not in treating COVID-19, because preliminary studies (the only ones available today) provide evidence of very low certainty. Furthermore, it is highly unlikely that a scientific body would recommend this intervention, since it has uncertain benefits and a high cost.

Based on: Preliminary evidence in humans (VERY LOW certainty of evidence)

 

Stem cells get their name from their ability to divide and then transform into any type of tissue. This means they can ‘procreate’ multiple cells of any type, something other cells cannot do. The treatment with stem cells consists of making them reach a damaged tissue, so that they ‘procreate’ there and thus regenerate said tissue. Additionally, these cells have many other properties, such as anti-inflammatory qualities.

The potential of stem cells to, in theory, recover virtually any damaged organ, has captured the attention of scientists and the imagination of the public. This has translated into, for example, improved management of certain malignant diseases of the blood, such as leukemia, in which stem cells regenerate the bone marrow after it is destroyed by chemotherapy or other treatments.

But, unfortunately, after 20 or 30 years of research, and hundreds or thousands of scientific articles, the verdict is rather lapidary: in the vast majority of diseases in which they have been tested, the promise of stem cells has not been fulfilled. And yet, despite this serious setback, the billionaire business associated with their use continues, refusing to acknowledge both scientific conclusions and regulators’ warnings.

It is not surprising, then, that in search for a cure for COVID-19, the indomitable promise of stem cells reawakens the interest of some scientists, particularly because of their possible anti-inflammatory effects. What has been surprising is the giant leap, in a matter of a few days, from the most embryonic preliminary investigation to the headlines of some of the most recognized media outlets in the world.

 

What does the evidence tell us today about the effectiveness of stem cells in COVID-19?

With the help of the COVID-19 L·OVE Working Group – formed with the objective of responding to the needs of evidence that the pandemic has generated – we conducted an exhaustive search for evidence (systematic review). We found only 2 preliminary studies in humans. One of them reports a single case, while the other, the one that hit headlines worldwide, evaluated only 7 patients and used no control group. This makes it impossible to draw conclusions about the efficacy of the treatment. So, in sum, there is no evidence today to confirm whether or not stem cells are effective in treating COVID-19.

 

Will we get new information on stem cells for COVID-19 in the near future? 

Yes. There are already multiple ongoing studies evaluating different types of stem cells in patients with COVID-19, especially in people with severe or acute respiratory distress syndrome.

 

When making a decision, what are the factors to put in the balance?

There are decisions that we must make even when there is no evidence. The use of stem cells as a COVID-19 treatment is such a case. So, in order to make the best possible choice, decision makers must put the following factors in the balance: scientific rationale, benefits, risks, costs, and other aspects.

Scientific rationale: There have been many experiments that suggest that stem cells should have a beneficial effect. However, laboratory findings have rarely been reproduced in actual patients.
Benefits: The existing evidence does not allow to draw any conclusions yet. And the indirect evidence – the type of evidence that we could extrapolate from other, similar diseases – is not promising.

Risks: In general, it is a low-risk therapy, although there are doubts about potential long-term risks.

Costs: Generally high or very high.

Other aspects to consider: There are other treatments in which stem cells are indeed necessary. An increased demand for stem cells due to COVID-19 puts the supply for those patients at risk. The unproven use of this therapy in COVID-19 fuels the questionable and lucrative market for stem cell treatment.

In summary, the arguments for and against using stem cells to treat COVID-19 are:

 

 

CONCLUSION
The available evidence to decide what role to assign to stem cells in the treatment of COVID-19 has very low certainty. This means we cannot assert whether they are effective or not. Now, evidence (or lack of evidence) alone is never enough to make decisions. In this case the balance between benefits and risks, the costs involved in this treatment, and the possibility that it generates negative externalities, make it VERY UNLIKELY that stem cells are recommended by some scientific establishment.