ME/CFS is characterized by weakness and/or excessive muscle weakness following activity. This device enables researchers to measure grip strength. Credit: © Charité | Anja Hagemann
Key Points:
- Scientists noticed a correlation between chronic fatigue syndrome and COVID-19 as the pandemic heightened during the summer of 2020.
- A group of researchers created a set of criteria to analyze fatigue symptoms reported by COVID-19 patients and symptoms of chronic fatigue syndrome.
- They discovered that COVID-19 caused chronic fatigue syndrome even in patients who suffered a mild case of the infection.
Fatigue, one of the symptoms commonly associated with COVID-19, has been reported by patients since the pandemic’s inception. As a result, experts have long theorized that SARS-CoV-2 may cause chronic fatigue syndrome (ME/CFS) in COVID-19 patients. Researchers at the Charité – Universitätsmedizin Berlin and the Max Delbrück Center for Molecular Medicine (MDC) have confirmed that hypothesis in a study recently published in Nature Communications.
The researchers reached their conclusions after studying the symptoms of 42 COVID-19 patients who reported relentless fatigue six months after developing the infection. Most of the study participants were unable to perform light work for more than two to four hours a day; some were unable to work and struggled to look after themselves.
For comparison, the researchers examined 19 age- and gender-matched individuals who developed ME/CFS following a similar period of illness due to a non-COVID-related infection.
Using the Canadian Consensus Criteria, the researchers found that approximately half of the 42 post-COVID patients met the diagnostic criteria for ME/CFS. While the other half presented with similar symptoms, their post-exertional malaise was milder and only lasted for a few hours.
Surprisingly, only 3 of the 42 patients examined needed hospital care during their acute SARS-CoV-2 infection, and none required oxygen. In fact, 32 of the patients met the WHO classification of mild COVID-1. Still, a mild diagnosis did not stave off long-term ME/CFS.
“We can therefore distinguish between two groups of post-COVID patients with severely impaired physical functioning,” said Judith Bellmann-Strobl, study co-author.
The team also found that hand grip strength was reduced in the majority of study participants. However, elevated levels of the cytokine interleukin 8 was linked to that reduced strength in post-COVID patients, while hand grip strength was correlated with the hormone NT-proBNP in the original ME/CFS patients.