In early 2024, a paper considering differences in the chemical processes in the body which involve small molecules involved in energy production (metabolites- the study of which is known as metabolomics), and immune alterations in people with long COVID (LC)- who also met the CDC/WHO criteria for ME/CFS (although exactly which versions used was unclear from citations), was published.
Notably, this study drew upon earlier work funded by ME Research UK – published in September 2005, which identified that in people with ME/CFS, levels of oxidative stress – a result of impaired energy production, were increased and associated with symptoms of ME/CFS – including post exertional malaise, and joint pain.
The new study examined blood samples from 75 people:
- 15 who had never been exposed to SARS-Cov-2 (the healthy control group)
- 60 who had been infected with PCR-confirmed SARS-CoV-2.
- 30 went on to develop symptoms of LC which persisted at 12 months after initial infection- symptoms were also consistent with a diagnosis of ME/CFS.
- 15 who although previously infected, recovered without any ongoing symptoms (the recovered group).
- 15 were hospitalised with acute COVID-19 infection.
Results suggested that that those with LC had several metabolomic differences compared with other study groups, including:
- Abnormally low adenosine Triphosphate (ATP) – an energy source within cells.
- Signs of chronic inflammation
- Markers of gut metabolites leaking into the blood (“leaky gut”).
- Significantly lower levels of certain protein molecules- amino acids, associated with normal brain functioning.
The authors of the study recognise that many of the abnormalities identified in those with LC in this study, have been observed in people with ME/CFS previously, suggesting similarities in disease mechanisms.
