has entered the room
posing as differential diagnosis.
Omicron [sic] amps up concerns about ["]long COVID["] and its causes
other than SARS-Cov-2 infection, regardless of a patient's "vaccine" status, actual medical history and commensurate maintenance drug regimen, or in/out patient COVID-indicated "cocktails".

Another is that latent viruses in the body, such as the Epstein-Barr [and varicella-zoster] virus that causes mononucleosis [that causes "shingles"], are reactivated. A recent study in the journal Cell pointed to Epstein-Barr in the blood as one of four possible risk factors, which also include pre-existing Type 2 diabetes and the levels of coronavirus RNA and certain antibodies in the blood. Those findings must be confirmed with more research.

A third theory is that autoimmune responses develop after acute COVID-19.

In a normal immune response, viral infections activate antibodies [T-cell, B-cell] that fight invading virus proteins. But sometimes in the aftermath, antibodies remain ["]revved up and mistakenly attack["] normal cells. That phenomenon is thought to play a role in autoimmune diseases such as lupus and multiple sclerosis

but not cancer