It's possible. But they do have an overactive immune system.
"Hyper-activation of the immune response against severe acute respiratory syndrome coronavirus 2 may result, in some cases, in development of unwanted autoimmune disorders"
https://www.wjgnet.com/2307-8960/full/v8/i17/3621.htm
ME/CFS (and those w/ Long Covid) have an overactive immune system and auto-antibodies
before getting sick.
And, (I don't have the article link handy, sorry) supposedly Covid put the autoantibodies into motion.
I think COVID is slightly different. TNF-a is key. But the IFN-y increase might just be a result of the autoantibodies they found in COVID patients against the other Type I Interferons. Or it might not. IFN-y can go up and down quickly, from the research I've seen.
But I think a good ME/CFS comparison is Parvovirus B19 and Enterovirus B.
Parvovirus B19 has been linked to a ton of autoimmune diseases (and ME/CFS). It creates a bunch of auto-antibodies (Collagen II, Phosphatidylserine, Cardiolipin, Angiotensin II type 1 (AT1) receptor, Rheumatoid Factor, DNA (ss and ds), β2-glycoprotein, myelin, etc). There's also a bunch of cross-reactivity to B19 antibodies and its proteins.
So, there's that. And also, acute B19 causes an abnormal immune response, resulting in impaired T cell-mediated cytotoxicity, and irregular cytokine function.
Then later, a bad case of Enterovirus B shows up. It's effect on our immune system results in all those auto-antibodies getting set into motion. If you didn't have reactivated EBV yet, then it will reactive at this time. The auto-antibodies will attack, disrupting your immune system. Dysregulated T cells, other lymphocytes, and cytokine production further disrupts your immune system.
Now you have rare case of non-cytolytic persistent Enterovirus B infection. Of course this will perpetuate your immune dysfunction.
And at this point, you are in a pretty deep hole that is difficult to climb out of. This representation could lead to any number of symptoms and conditions.
(btw - There are still two things about Parvovirus B19 that I'm still researching and have yet to confirm. I'm not sure about the extent of damage and autoimmunity one can get from merely an acute B19 infection. And I still don't know if chronic diseases and autoimmune conditions occur more w/ persistent B19 infections, and/or the best way to test for persistent B19 infections. All I know is there is more to B19 than meets the eye. I will find answers. I will share more when I find out)