Increasing research has linked immune cells with post viral fatigue syndrome (PVFS) – an umbrella term which includes ME/CFS, fibromyalgia, and long COVID.
However, there is uncertainty around whether the relationship between the two is ‘causal’.
In research, a causal relationship occurs when one event – the cause – brings about another event – the effect. Causation is very hard to prove, and often the evidence from many research studies using different methods must be considered in a process called triangulation.
A study published in the ‘Virology journal’ aimed to provide evidence of the causal connection between immune cells and PVFS.
The researchers compared information from 195 people with PVFS with that of 382,198 controls. This information was obtained from the FinnGen consortium, which contains biobank samples and health register data for around 10% of the Finnish population (more than 500,000 people).
Findings were complex, but the researchers found 28 immune cell types that showed potential causal associations with PVFS. Notably, the team stated that these findings indicate “compelling evidence of a probable causal link between immune cells and PVFS”.
Before a conclusion can be made regarding the causal link between immune cells and PVFS, more research is needed to validate these findings, and to assess whether the same results would be seen for different groups of people with PVFS – such as those with ME/CFS, those with fibromyalgia, and those with long COVID. It would also be important to consider how different demographic characteristics – such as sex, ethnicity, and age – affect the findings.
