An infection caused by a virus or a bacteria or in the case of cancer, cells of your own body that have gone rogue.
People tend to feel ill/sick when they have an infectious disease because their body is fighting off that infectious disease. since the body if fighting of that disease it can have a toll on that individuals physical health making them tired.
The immune system
Vaccines put either a dead or weak version of the disease into your body. Your bodies immune system will then attack the cells and form antibodies. The antibodies are then permanently in your system and if you get the disease again it will be able to fight it fact since it already has the cells in your body to fight it. When someones body is fighting a disease their immune system is already working at fighting what is in their body. Adding a vaccine could make them even sicker.
antibiotics
She was fighting off diptheria.
The correct spelling is "battling" in the context of fighting a disease.
If the body's immune mechanism is not capable of fighting then the bacteria produces disease.
HIV infection or AIDS is the disease, which you have infection by HIV virus, that attacks disease fighting cells in the blood.
AIDS is caused by the HIV virus, which attacks disease-fighting cells.
vaccine
none, heart disease is not that kind of disease.
Vaccinations work by injecting a small amount of a weakened or dead form of the disease you are preventing. This works because the bodies defenses learn how to kill the disease very quickly and can fight it off very easily the next time they encounter it. If you tried to vaccinate a person who is already infected with the disease you are trying to prevent, than you would just be injecting more of the disease into a body that is already fighting the disease off. For most diseases, actually becoming infected with the disease serves as a vaccination in itself. It works the same way, except that the body has a much harder time fighting the disease off, because the microorganisms that cause the disease clearly did not enter the body dead, as is the case with deliberate vaccinations.