[runemadsen]

There is lots and lots of research into the similarities of Long Covid and other post-viral illnesses despite the fact that people only recently started reporting these symptoms:

"This study supports prior findings that ME/CFS occurs with high prevalence among those who have persistent COVID-19 symptoms." - https://www.mdpi.com/2035-8377/15/1/1

Long Covid symptoms are not vague. If you argue this, you have not done enough research into what people are battling. A majority of Long Covid haulers suffer from PEM (Post Exertional Malaise) which is a primary symptom of ME/CFS, and even thought research on this subject has been performed for decades, We currently don't understand what causes it. There are many theories for ME/CFS which could fit well with Long Covid, including an activation of the Epstein-Barr virus which causes neuroinflammation, and if this neuroinflammation primarily centers on the brain, it explains all the symptoms that people are reporting.