The HIV/AIDS hypothesis postulates that a new infectious epidemic of immunodeficiency in humans – acquired immunodeficiency syndrome ("AIDS") – is the result of infection by an exogenous retrovirus known as human immunodeficiency virus ("HIV"). The hypothesis also includes the following claims:
- HIV is transmitted sexually, via semen, and also via blood and perinatally.
- HIV causes, in some fashion, destruction of CD4 helper lymphocytes, which is taken to be the hallmark of acquired immunodeficiency.
- Within weeks after infection, HIV induces antiviral immunity and antibodies, and prior to this antiviral immunity, HIV may cause a slight mononucleosis-like illness.
- However, after a "latency" period usually ranging between 5-10 years, although potentially up to 15-20 years or more, HIV realises its potential to overcome the body's immune system.
- The destruction of CD4 helper lymphocytes, usually accompanied by an increase in cytotoxic CD8 lymphocytes, causes a breakdown in cell-mediated immunity, leaving the immune system vulnerable to various opportunistic infections which would not normally be serious.
- This acquired immunodeficiency is the basis for about 30 previously known diseases, including PCP, Kaposi's sarcoma, tuberculosis, candidiasis, dementia, diarrhea, and cervical cancer.
Given the inability of the HIV/AIDS hypothesis to make accurate predictions     and the inability of the mainstream AIDS researchers to provide plausible biological explanations of how HIV is supposed to kill T-cells , or perhaps more accurately, the ability of mainstream AIDS researchers to provide a bewildering array of hypothetical explanations  , , it is difficult to state what is meant by the "HIV/AIDS hypothesis". Indeed, John Maddox, former editor of Nature magazine, has given a simple explanation of the hypothesis: "HIV causes AIDS, in some manner not understood; most of those infected will develop the disease."  Note that Maddox's cryptic version of the hypothesis contains almost no real content and is virtually worthless in terms of predictive or explanatory power.