As mentioned previously, I have a chronic auto-immune disorder/illness, ME/CFS (or just "M.E."). Through that I got to know some other persons with same or similar long-term problems. The only reason I joined Facebook years ago was that I started a very humble local support group, and "everybody" was already on FB (sigh.. yes I know). I sort of drifted off, have not much contact with similar "victims" except a very few, so my connection to the "community" is rather limited these days. Some with ME are very sensitive to medications, including vaccines. For a few it even started with a vaccination.
Now, I have heard second hand about a few with M.E. that has taken these mRNA "vaccines" and they are actually feeling a bit better. I have no more specific info than that. I suspect there are those that refuse any vaccinations or "vaccinations", too. However, as these "vaccines" tinker with immune response it is not out of the question some individuals with auto-immune disorders actually get a bit better, short or long term. But then it is not a vaccine, it is treatment, a serum or otherwise method to help healing. Not protecting nor preventing. Ironically, if some people get better from the "vaccine", I would argue is not a vaccine in the ordinary sense of the word.
One more thing about M.E.: I have heard women with M.E. who during pregancy feel almost fully healthy. Pregnancy is a risk, the woman can also get worse, as being pregnant is hard work for an already fatigued and pained body. During pregnancy, the woman's body "turns down" its immune system, as she has a rather foreign body inside her own. For some cases of M.E. that means their wacko immune system "relaxes" a bit and the person is a lot better. So it is a lottery. One would not recommend pregancy as a "temporary cure" for M.E., as things can go very wrong.
mRNA holds (maybe great) promise for indivudualizing medicine, something the ordinary school of medicine is quite bad at. Unless you are fortunate to have an experienced general practioner that seen a lot without getting jaded. Vaccines are collective, not individualized. Those that got lessened chronic problems from it, did it out of luck. As the "treatment" was not preceeded by diagnosis.
It is a lottery how your body responses. Furthermore, they should actually research more for the individualizing trajectory.
But, of course, collectivism is way more profitable, lazy and faster.
Que serum, serum; whatever will be, will be?