I'm calling it now. Long term covid-19 disease will be found to be mostly a side effect of abnormal cell-cell fusion due to the membrane fusion mediating properties of the basic terminal of the protease cleaved spike protein in sars-cov-2 particles. There are many studies in lung, heart, and cell culture model tissues showing abnormal cell fusion happens, and happens far more with sars-cov-2 than it does with sars-cov-1 (or other lipid enveloped viruses). The inflammatory effects of these persistent merged cells would cause the weird immune response (ie, parasitic factors being expressed along with viral throwing immune response off) and long term issues in the surrounding tissues of the organ.
Of course there's a lot more going on in long term covid-19 than just this accidental side-effect cell membrane fusion. Stuff with the angeotensin signaling being completely messed up to due competitive binding by sars-cov-2 spike RBD, and the circulatory damage this causes can't be ignored. Or even the normal cytotoxic effects of all viral infection. But the cell fusion bit has it's role to play and I think it's an important one.
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