What is the difference between a disease and an illness?
In essence, “illness” is the patient’s subjective way of describing not feeling well.
“disease” is the objective determination by a doctor of what, in the body, is causing the patient to feel unwell; or what is occurring in the patient’s body, out of the patient’s awareness, that will have detrimental effects in the future.
It would be better, though, if you really want to understand the difference, to read:
From an insurance perspective, diseases do not include injuries, but illness does. Seeing a doctor for a flu shot or for physical when you are asymptomatic would not be an illness. Pregnancy and childbirth were not considered illness when I was young, but they are now, in many (all?) states. A failed suicide attempt is typically an injury, and might be considered the result of mental illness, but policies that cover only injuries usually specify that they cover only accidental injuries, thus sudesteppinh the question of whether it is an injury or a disease.