If HIV is allowed to reproduce, or "replicate," inside the body, it will cause damage to the immune system. Ultimately, the immune system gets so weak that the body becomes vulnerable to other diseases. This is the point at which a person is usually diagnosed with AIDS, and the other diseases they get can eventually cause death. For adults who live in wealthy nations—such as the United States—the average time between becoming infected with HIV and the development of AIDS is 10 years.