

I’m not familiar with COVID, but it does sound to me like you’ve got long COVID. I’ve got no advice on that front - frankly, I don’t think anybody really knows what’s up with that. I get the impression that that’s why the advice that you’ve received so far are primarily focused on treating symptoms.
If your hypothesis is correct that your antibiotic is helping through its immunomodulatory effects, then it looks like it’s acting primarily through inhibiting cytokine production. Messing with cytokines will certainly affect your ability to fight off infections, since that’s how your body signals to immune cells that there’s something wrong. Of course, immunity is all about balance, and you don’t need to block cytokine signaling completely in order to decrease it to manageable levels… A brief search shows that there are inhibitors for TNFa, which based on your links seem to be what you’re leaning towards as the molecular mediator.
Have you considered bringing this up to your doctor? I’m not sure how feasible it would be to do a “trial run” with one of these inhibitors to see if it helps your symptoms. However, it may be simple enough to ask for a blood test to measure the amounts of different cytokines in your blood. My understanding (don’t trust me on this - I’m not a clinician) is that standard blood tests don’t typically measure cytokines, which is potentially why your blood tests so far haven’t been able to pick anything up out of the ordinary. That would at least help rule in/out any possible causes.
I will also point out an alternative hypothesis that might be worth considering - it could be that the antibiotic is depleting your microbiome, which would reduce the same cellular pathways that your antibiotic is said to inhibit due to your cells being in less contact with bacteria. Have you tried other antibiotics, and did they have a similar effect?







That makes sense, but unfortunately in a frustratingly unhelpful way. NF-kB is the central mediator of cellular immunity. What that means is that everything that needs an immune response triggers NF-kB and everything immunity-related gets activated due to NF-kB. Likewise, TNFa is the prototypical pro-inflammatory cytokine. It’s remarkably good at triggering immune responses in a wide variety of cells, and every immune response that I know involves TNFa in some way.
In other words, having inflammatory symptoms be caused by NF-kB>TNFa is less of a “that’s an interesting pathway” and more of a “yeah, of course NF-kB and TNFa would be involved, what’s new?”
The concern is that we don’t really know what’s activating NF-kB in the first place, and so as a result you can’t really fix the core problem. And because NF-kB and TNFa are involved in basically every immune process, it’s hard to tell if these proteins are the ones actually responsible for causing your symptoms. You’d be operating on a hunch, essentially. Though I will say that your unusually nondescript and broad symptoms do seem roughly in line with what I would expect from TNFa signaling.
All that to say, I’m not a doctor and I have no experience with translating knowledge into practicable therapies, so definitely talk to a doctor about it. But TNFa is very easy to detect in your blood, and if TNFa is causing your symptoms, then it’s really easy to just check to see if you’ve got high TNFa in your blood when you’re taking the antibiotics vs. when you’re not. If you had the money, you could even buy a test kit yourself and get an answer in a single day, assuming you know how to use the kit