STI: See Sexually Transmitted Infection.

Safe injection sites: See Needle Syringe Exchange Programme.

Safe sex: Sexual activities in which no potentially harmful bodily fluids are exchanged.

Self-care: The manner in which an HIV/AIDS patient without a professional medical background cares for himself or herself. Care encompasses such facets of health care as nutrition, precautions, health promotion and maintenance. The patient practicing self-care can be guided by a medical professional and supported by family and friends.

Seroconversion: The time at which a person’s antibody status changes from negative to positive.

Seronegative: Negative result in a blood test.

Seropositive: Positive result in a blood test.

Serosurveillance: Collecting blood samples for the purpose of surveillance.

Sex worker: A person who has sex with others to acquire money, goods or favours, in order to make a full-time or part-time living for him or herself.

Sexually transmitted infection (STI): Any infection whose primary route of transmission is via sexual intercourse.

“Shooting up”: The intravenous injection of drugs.

Side effects: Unintended effects of a drug or other treatment. Some side effects are unwanted, harmful, or toxic, while some may be beneficial.

Situation assessment: A study of the qualities of a situation.

Situational analysis: A detailed examination/study of a situation designed to discover more about its nature.

Stem cell: Bone marrow cells from which all red blood cells are produced.

Sterilized needle: A needle that is free of micro-organisms and therefore will not transmit disease or infection.

Stigma: A social label attached to a person or condition, usually formed by public perception and opinion.

Strain: Subgroup of a species (in this case, the HIV/AIDS virus) that differs in trivial ways from similar groups.

Subtype: A genetic variant.

Surveillance: The ongoing and systematic collection, analysis, and interpretation of data about a disease or health condition, also referred to as epidemiologic surveillance.

Symptom: Any condition occurring because of a disease. For example, coughing could be a symptom of a cold, bacterial infection, or lymphoma.

Syndrome: A group of symptoms and/or diseases that characterise a specific condition.

Systemic: Affecting the entire body.