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Glossary of HIV/AIDS Terms

for Health Care Providers

Glossary of HIV/AIDS Terms


A family of gram-negative bacteria, found in undercooked poultry or eggs, that are a common cause of food poisoning. Salmonella infection can be more severe in people with HIV.

Salvage therapy

Also referred to as rescue therapy. A treatment effort for people whose antiretroviral regimens have failed at least two times and who have had extensive prior exposure to antiretroviral agents.


A malignant (cancerous) tumor of the skin and soft tissue.

Seborrheic dermatitis

A chronic inflammatory disease of the skin of unknown cause or origin, characterized by moderate redness; dry, moist, or greasy scaling; and yellow crusted patches on various areas, including the mid-parts of the face, ears, above the orbit of the eye, umbilicus (the navel), genitalia, and especially the scalp.

Secondary prophylaxis

See Maintenance therapy.

Sensitivity (of a test)

The sensitivity of a test is the probability of it giving a positive result if infection is truly present. As the sensitivity of the test increases the proportion of false negatives decreases.


The presence of harmful microorganisms or associated toxins in the blood.


Trade name of trimethoprim/sulfamethoxazole.

See Trimethoprim/sulfamethoxazole (TMP/SMZ, TMP/SMX, cotrimoxazole, Bactrim, Septra).


The development of antibodies to a particular bacteria, virus, or vaccine. When people develop antibodies to HIV, they seroconvert from antibody negative to antibody positive. It may take from as little as 1 week to several months or more after infection with HIV for antibodies to the virus to develop. After antibodies to HIV appear in the blood, a person should test positive on antibody tests.

See Incubation period; Window period.


The rate of new infections within a specific target population within a given period of time.

Serologic test

Any number of tests that are performed on the clear fluid portion of blood. Often refers to a test that determines the presence of antibodies to antigens such as viruses.


As related to HIV infection, the proportion of persons who have serologic (i.e., pertaining to serum) evidence of HIV infection at any given time.


Results of a blood test for specific antibodies.


The clear, thin, and sticky fluid portion of the blood that remains after coagulation (clotting). Serum contains no blood cells, platelets, or fibrinogen.

Set point

The measurable holding point or balance between the virus and the body's immune system reported as the viral load measurement. The viral set point is established within a few weeks to a few months after infection and is thought to remain steady for an indefinite period of time. Set points are thought to determine how long it will take for disease progression to occur.

Sexually transmitted disease (STD)

Also called venereal disease (VD) (an older public health term) or sexually transmitted infection (STI). STDs are infections spread by the transfer of organisms from person to person during sexual contact. In addition to the "traditional" STDs (syphilis and gonorrhea), the spectrum of STDs now includes HIV infection; Chlamydia trachomatis infections; human papillomavirus (HPV) infection; genital herpes; chancroid; genital mycoplasmas; hepatitis B; trichomoniasis; enteric infections; and ectoparasitic diseases (i.e., diseases caused by organisms that live on the outside the host's body). The complexity and scope of STDs have increased dramatically since the 1980s; more than 20 microorganisms and syndromes are now recognized as belonging in this category.


(Serum glutamic oxaloacetic transaminase) Also known as AST (aspartate aminotransaminase), a liver enzyme that plays a role in protein metabolism. Elevated serum levels of SGOT are a sign of liver damage from disease or drugs.


(Serum glutamic pyruvate transaminase) Also known as ALT (alanine aminotransaminase), a liver enzyme that plays a role in protein metabolism similar to that of SGOT. Elevated serum levels of SGPT are a sign of liver damage from disease or drugs.


See Herpes zoster.

SHIV (Simian human immunodeficiency virus)

A genetically engineered virus having an HIV envelope and an SIV core.

Side effects

The actions or effects of a drug (or vaccine) other than those desired. The term usually refers to undesired or negative effects, such as headache, skin irritation, or liver damage. Experimental drugs must be evaluated for both immediate and long-term side effects.

Simian immunodeficiency virus (SIV)

An HIV-like virus that infects monkeys, chimpanzees, and other nonhuman primates.


Inflammation of the nasal cavity and sinuses.

Specificity (of a test)

The specificity of a test is the probability of the test providing a negative result if the disease is truly absent. As the specificity of a test increases, the proportion of false positives decreases.

Spinal tap

See Lumbar puncture.


An enlarged spleen.


Mucus and other matter that is brought up from the lungs by coughing.

Sputum analysis

Method of detecting certain infections (especially tuberculosis) by culturing of sputum — the mucus matter that collects in the respiratory and upper digestive passages and is expelled by coughing.

Standards of care

Treatment regimen or medical management based on state-of-the-art patient care.


Type of bacteria that may cause various types of infection.

Stem cells

Cells from which all blood cells derive. Bone marrow is rich in stem cells.

Stevens-Johnson syndrome

A severe and sometimes fatal form of erythema multiforme that is characterized by severe skin manifestations; conjunctivitis (eye inflammation), which often results in blindness; Vincent angina (trench mouth); and ulceration of the genitals and anus.


Inflammatory diseases of the mouth (e.g. canker sores, thrush, fever blisters) having various causes, such as mechanical trauma, irritants, allergy, vitamin deficiency, or infection.


Subgroup of a species. For HIV, different types of HIV such as HIV-1, HIV-2, clade A, clade B, etc.

Study endpoint

A primary or secondary outcome used to judge the effectiveness of a treatment.

Subclinical infection

An infection, or phase of infection, without readily apparent symptoms or signs of disease.

Subcutaneous (SQ)

Beneath the skin or introduced beneath the skin (e.g., subcutaneous injections).

Subunit HIV vaccine

A vaccine that is based on only part of the HIV molecule.

Sulfa drug

A sulfonamide drug used to treat bacterial infections. These drugs inhibit the action of p-aminobenzoic acid, a substance bacteria need in order to reproduce.


Synthetic derivatives of p-aminobenzene sulfonamide.

See Sulfa drug.

Suppressor T cells

(T8, CD8) Subset of T cells that halts antibody production and other immune responses.

Surrogate markers

Variables (measures) that are followed in clinical trials when the variable of interest cannot be conveniently observed in a direct manner. Two commonly used surrogate markers in HIV studies are CD4+ T-cell counts and quantitative plasma HIV RNA (viral load).


Vulnerable or predisposed to a disease or infection.


Any perceptible, subjective change in the body or its functions that indicates disease or phases of disease, as reported by the patient.


A group of symptoms as reported by the patient and signs as detected in an examination that together are characteristic of a specific condition.

Synergism, Synergistic

An interaction between two or more treatments that produces or enhances an effect that is greater than the sum of the effects produced by the individual treatments.


A primarily sexually transmitted disease resulting from infection with the spirochete (a bacterium) Treponema pallidum. Syphilis can also be acquired in the uterus during pregnancy.


Concerning or affecting the body as a whole. A systemic therapy is one that the entire body is exposed to, rather than just the target tissues affected by a disease.