The immune system is one of the most important systems of the human body. It is very similar to a computer’s antivirus system. The system searches for viruses and cleans all the cells in the body. The cells that do this are called lymphs. The lymphs are produced in bone marrow, the appendix, spleen, tonsils, and thymus. The lymphocytes are one of the many types of lymphs. There are nearly one trillion lymphocytes in a body.
Another type of cell is the CD4+ cell. The HIV/AIDS virus attacks the CD4+ cells so they can not function properly. The purpose of the CD4+ cells is to recognize that a virus has entered the body and alert the rest of the immune system. It is also supposed to memorize the structure of the invading virus. If the CD4+ cells are destroyed, your immune system will not know to fight of the disease and, you will become susceptible to the same disease multiple times.
When a person is given a shot, the doctor is injecting a dead version of a virus into them. The immune system (CD4+ cells) then realizes that there is a foreign substance in the body and tries to fight it off. When the lymphs encounter the dead virus, they learn of what substance it is created out of and memorize it. If the real form of the virus enters into the body, the immune system will know how to kill it and do so before the virus can do any damage to the body.
It is important to understand that AIDS is a virus that damages the immune system, and you cannot die from AIDS, People who die with AIDS are killed by the infections that are not stopped by the immune system. AIDS can even turn the common cold into a life and death situation.