AIDS, sociological studies of The Acquired Immune Deficiency Syndrome (AIDS) is a complex of symptoms and ultimately deadly infections caused by the Human Immuno-deficiency Viruses (HIV). An initial period of high infectivity is followed after some three months by the appearance of HIV antibodies, which signal a reaction to the HIV infection, and on which the main tests for the condition are based. Following what are often years of symptom-free living, the body finally succumbs to normally rare and unusual diseases, especially PCP (Pneumocystis Carinii Pneumonia) and KS (Karposi's Sarcoma). The main vehicles of transmission are the bodily fluids, especially blood (blood transfusion, intravenous drug use, and vertical transmission from mother to child) and semen, chiefly by means of penetrative sexual intercourse (homosexual or heterosexual). The World Health Organization distinguishes three zones and patterns of infection: Asia, which is now the principal growth area of infection; the African continent (site of the initial discovery, and where transmission is primarily heterosexual in form); and industrialized Western nations (where an epidemic started in the 1980s, with infection primarily transmitted by homosexual intercourse, and intravenous drug needle-sharing). In 1996 it was estimated that 30 million people were infected by HIV and 10 million living with AIDS.

Sociology has contributed in various ways to the understanding and control of AIDS/HIV infection. Studies of sexual networks of transmission were crucial for identifying the virus in 1982. Sociology has also informed national and large-scale studies of sexual and drug-taking behaviour, both KABP (Knowledge, Attitudes, Behaviour and Practices), and the more innovative and qualitative research that is necessary to monitor the prevalence and incidence of high-risk behaviour and risk-taking activity. Theories of risk-taking have also developed from early reliance on the Health Belief Model to contextual and strategic aspects and the study of collective and community response.

Because the activities implicated in the transmission of AIDS are in many societies either illegal or tend to involve already marginalized groups, sociological studies of gender, deviance, and sexual identity have been used to focus research studies. Techniques have been devised to identify and sample hard-to-reach and ‘hidden populations’, such as intravenous drug-users and non-gay-identified men who have sex with men, by extending existing sociological and anthropological methodologies. Methods such as sexual diaries have been employed to elicit intrusive information as non-reactively as possible.

The main resources for the study of sociological features of AIDS include the annual Social Aspects of Aids conference and volume, and the biennial WHO/UNAIDS publication edited by J. Mann et al. , Aids in the World
.