Long COVID (LC), post-viral fatigue syndrome (PVFS), and ME/CFS, are characterized by clusters of symptoms, of which there are many. Patients may have some or all of these symptoms. Around half of people reporting long COVID at six months, and everyone with ME and PVFS, have a symptom called post-exertional malaise (PEM) in common. PEM is a disproportionate and disabling worsening of physical and cognitive ability after trivial activity. Within both LC and ME/CFS there are phenotypes, “flavours,” corresponding to particular disease processes. Along with these phenotypes there are even more hypotheses which attempt to explain the mechanisms behind them.

As a patient, in order to figure out what treatment options to pursue, one must determine roughly what it actually is that one is suffering from. This is why, while a formal diagnosis of ME/CFS, Long COVID, etc might be useful from the perspective of someone’s social security or insurance, it means the square root of fuck all when it comes to medical treatment and actually getting better. It also makes science difficult—how do you get statistically significant insights from 100 people with ME/CFS when these people have 15 different disease processes?

There are two options available to someone who is trying to figure out what is wrong with them:

  1. Testing
  2. Treatment as test

Both of these require precious energy, time and money, publicly-available testing and treatments, and, crucially, an informed and epistemically-sensitive patient community. In the UK at least “publicly-available” means outside of the NHS, which actually seeks to halt testing for people with complex conditions once a label, like ME/CFS, has been slapped on them.

Classifying, in the scientific sense, the subsets of ME/CFS and Long COVID is crucial for meaningful individual and institutional (medicine, academia) progress. It will literally save lives.