What are HIV and AIDS?
HIV stands for human immunodeficiency virus. This is a virus in the group of viruses called retroviruses. HIV destroys cells in the body, called CD4 T cells. CD4 T cells are a type of white blood cell (a lymphocyte). These are important cells involved in protecting the body against various bacteria, viruses and other germs. HIV actually multiplies within CD4 cells. HIV cannot be destroyed by white blood cells, as it keeps on changing its outer coat, so protecting itself.
AIDS stands for acquired immunodeficiency syndrome. This is a term which covers the range of infections and illnesses which can result from a weakened immune system caused by HIV. Because antiretroviral therapy (ART) has altered the way we think about the condition, the term late-stage HIV is being increasingly used instead of AIDS.
HIV and AIDS are not the same thing and people who get HIV infection do not automatically develop AIDS. AIDS is unlikely to develop in people who have been treated in the early stages of HIV infection. Even in people who do not receive treatment, there is usually a time lag of several years between first being infected with HIV and then developing infections and other AIDS-related problems. This is because it usually takes several years for the number of CD4 T cells to reduce to a level where your immune system is weakened.