Symptoms of Long COVID-19, Chronic Fatigue Syndrome Overlap

In some people who develop COVID-19[1] and experience lasting symptoms, those symptoms — including severe fatigue — closely resemble chronic fatigue syndrome and may have biological similarities, according to a new study published in the journal Proceedings of the National Academy of Sciences of the United States of America[2].

As the study authors notes, chronic fatigue syndrome (also known as myalgic encephalomyelitis) is a debilitating condition that can last for years, causing symptoms like profound fatigue, malaise after physical exertion, lack of restorative sleep, cognitive deficits, and a drop in blood pressure when getting up from a sitting or lying position. It often develops in the aftermath of a bacterial or viral infection. While some doctors have been skeptical of chronic fatigue syndrome — questioning whether it’s caused by biological abnormalities, or might be mostly psychological in nature — the authors of the latest study pointed out that there are distinct biological abnormalities seen in both chronic fatigue syndrome and long COVID-19.


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Among the commonalities between chronic fatigue syndrome and long COVID-19 that the study authors identified is redox imbalance (also known as oxidative stress), in which there is a disruption in levels of oxidants — molecules from within or outside the body that can damage cells — and antioxidants, molecules that can protect against this damage. Other commonalities include systemic (body-wide) inflammation, brain inflammation, and a hypometabolic state (reduced metabolism). What causes these changes in chronic fatigue syndrome isn’t well understood, and they have only recently been identified in long COVID-19 — but understanding their causes may lead to the development of treatments for both conditions.

Up to 75% of those with COVID-19 experience long-lasting symptoms

As noted in a UPI article[4] on the study, as many as 75% of people who develop COVID-19 experience symptoms that last for months, potentially including severe fatigue. This can happen even in people who initially develop mild or moderate symptoms of COVID-19, although lasting debilitating symptoms are more common in people who initially develop severe COVID-19. As we wrote earlier this year[5], one study found that three to nine months after the onset of COVID-19, fatigue and loss of taste or smell were each seen in about 14% of people. Another study found[6] that about half of all people who developed COVID-19 experienced symptoms of depression[7] months later.

Another sign that COVID-19 can lead to lasting biological changes is the increased risk of diabetes seen in people who develop the illness. A study from earlier this year[8] found that among people who survived the first 30 days after developing COVID-19, over the next six months, there were an additional 6.5 new cases of diabetes for every 1,000 people who weren’t hospitalized for COVID-19, and an additional 37 new cases of diabetes for every 1,000 people who were hospitalized for COVID-19.

It is “imperative that increased research be focused on both long COVID-19” and chronic fatigue syndrome, the authors of the latest study wrote. Fortunately, they noted, the United States and several other countries have committed funding to study long-term chronic illness related to COVID-19.

Want to learn more about coronavirus and diabetes? Read our latest COVID-19 updates[9].

  1. COVID-19:
  2. Proceedings of the National Academy of Sciences of the United States of America:
  3. sign up for our free newsletters:
  4. UPI article:
  5. wrote earlier this year:
  6. Another study found:
  7. depression:
  8. study from earlier this year:
  9. COVID-19 updates:

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