I think it’s from dysautonomia impairing the immune system. Pretty much anything that affects the autonomic nervous system, which is a huge number of very different things, can trigger dysautonomia. The rational for my reasoning is that the propensity for cancer appears to occur at roughly the same rate as the propensity for dysautonomia regardless of the cause of dysautonomia.

Covid and the Covid Vaccine are both triggers for dysautonomia, I presume because both use the spike protein. The vaccine triggered mine but I have a strong genetic propensity for it anyway with multiple inherited anxiety disorders.