Research has identified 4 factors in whether Covid is likely to become long-term Covid. I quote from the newspaper story about it:
One of the four factors researchers identified is the level of coronavirus RNA in the blood early in the infection, an indicator of viral load. Another is the presence of certain autoantibodies — antibodies that mistakenly attack tissues in the body as they do in conditions like lupus and rheumatoid arthritis. A third factor is the reactivation of Epstein-Barr virus, a virus that infects most people, often when they are young, and then usually becomes dormant.
The 4th is being Type II diabetic but they don't know if that is the only disease involved. The other 3 factors are how a body reacts TO the virus.
Blicky to actual study.