Glossary

Acquired Immunodeficiency Syndrome (AIDS)
A disease of the immune system due to infection with HIV. HIV destroys the CD4 lymphocytes (CD4 cells) of the immune system, leaving the body vulnerable to life-threatening infections and cancer. Acquired immunodeficiency syndrome (AIDS) is the most advanced stage of HIV infection.

Acute HIV Infection
Also Known As: primary HIV infection
Early stage of HIV infection that extends approximately 2 to 4 weeks from initial infection until the body produces enough antibodies to be detected by an HIV antibody test. Because the virus is replicating rapidly, HIV is highly infectious during this stage of infection.

Adherence
Taking medications exactly as prescribed. Poor adherence to an HIV treatment regimen increases the risk for developing drug-resistant HIV and virologic failure.

AIDS Service Organisation (ASO)
A non-governmental organisation that provides services related to the prevention and treatment of HIV and AIDS.

AIDS-Defining Condition
Any HIV-related illness included in the Centres for Disease Control and Prevention’s (CDC) list of diagnostic criteria for AIDS. AIDS-defining conditions include opportunistic infections and cancers that are life-threatening in a person with HIV.

Antiretroviral (ARV)
A drug used to prevent a retrovirus, such as HIV, from replicating. The term primarily refers to antiretroviral (ARV) HIV drugs.

Antiretroviral Therapy (ART)
Also Known As: Combination Therapy, Combined Antiretroviral Therapy, Highly Active Antiretroviral Therapy
The recommended treatment for HIV infection. Antiretroviral therapy (ART) involves using a combination of three or more antiretroviral (ARV) drugs from at least two different HIV drug classes to prevent HIV from replicating.

Antiviral
A drug used to prevent the growth or replication of viruses.

Asymptomatic HIV Infection
Also Known As: Clinical Latency
Stage of HIV infection during which there are no symptoms of HIV infection. During this stage of HIV infection, which varies in length from person to person, HIV slowly destroys the immune system. Antiretroviral therapy (ART) can prevent the onset of symptomatic HIV infection and AIDS.

Autoimmune Disorder
A condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue. Autoimmune disorders may be caused by drugs used to treat opportunistic infections.

Baseline
An initial measurement used as the basis for future comparison. For people infected with HIV, baseline testing includes CD4 count, viral load (HIV RNA), and resistance testing. Baseline results are used to guide HIV treatment choices and monitor effectiveness of antiretroviral therapy (ART).

CD4 Count
Also Known As: CD4 Cell Count, CD4 Lymphocyte Count

A laboratory test that measures the number of CD4 lymphocytes (CD4 cells) in a sample of blood. In people with HIV, the CD4 count is the most important laboratory indicator of immune function and the strongest predictor of HIV progression. The CD4 count is one of the factors used to determine when to start antiretroviral therapy (ART). The CD4 count is also used to monitor response to ART.

CD4 Receptor
A protein found primarily on the surface of CD4 lymphocytes (CD4 cells). To enter a host cell, HIV binds to a CD4 receptor and a coreceptor on the host cell.

CD4 T Lymphocyte
Also Known As: CD4 Cell, Helper T Cell
A type of lymphocyte. CD4 lymphocytes (CD4 cells) help coordinate the immune response by stimulating other immune cells, such as macrophages, B lymphocytes (B cells), and CD8 lymphocytes (CD8 cells), to fight infection. HIV weakens the immune system by destroying CD4 cells.

Chlamydia
A common sexually transmitted infection caused by the bacterium Chlamydia trachomatis. Chlamydia often has mild or no symptoms, but if left untreated, it can lead to serious complications, including infertility. Chlamydia may increase the risk of HIV transmission.

Clinical Progression
Advance of disease that can be measured by observable and diagnosable signs or symptoms. For example, HIV progression can be measured by change in CD4 count.

Clinical Trial
A research study that determines whether a new drug (or other intervention) is both safe and effective for humans. There are two main types of clinical trials: interventional trials and observational trials.

Communicable Disease
An infectious disease that is contagious.

Comorbidity
When a person has two or more diseases or conditions at the same time. For example, a person with high blood pressure may also have heart disease.

Concordant Couple
Sexual partners in which both partners are infected with a sexually transmitted infection, such as HIV.

Condom
A device used during sexual intercourse to block semen from coming in contact with the inside of the vagina. Condoms are used to prevent the transmission of sexually transmitted infections, including HIV, and to reduce the likelihood of pregnancy. The male condom is a thin rubber cover that fits over a man’s erect penis. The female condom is a polyurethane pouch that fits inside the vagina.

Contagious Disease
And infectious disease that can be transmitted from person to person. Transmission can occur through direct physical contact, such as by touching or having sex with an infected person; through indirect contact, such as touching or using an object that an infected person has touched or used; or through close proximity, such as being exposed to an infected person’s sneeze or cough.

Contraindication
A symptom or condition that makes a particular treatment or procedure inadvisable because of potential for harm. There are two types of contraindications: relative and absolute.

Cross Resistance
Resistance to one or more drugs that occurs as a result of previous exposure to a similar drug. For example, HIV resistance to one nonnucleoside reverse transcriptase inhibitor (NNRTI) drug may produce resistance to all drugs in the NNRTI drug class, including drugs never used. Excluding all drugs in a drug class from an HIV regimen (drug sparing) is a strategy used to prevent cross resistance.

Definitive
For certain; without a doubt. An initial positive HIV antibody test must be confirmed by a positive Western blot test for a person to have a definitive diagnosis of HIV infection.

Discordant Couple
Sexual partners in which only one partner is infected with a sexually transmitted infection, such as HIV, and the other partner is not infected.

Dosage
The administration of individual doses of a medication as part of a medication regimen, usually expressed as quantity per unit of time. For example, a prescribed dosage might consist of 25 mg of a medication given 3 times a day for 6 days.

Dose
The quantity of a medication to be given at one time, or the total quantity of a medication administered during a specified period of time. For example, a patient might receive an initial medication dose of 50 mg, and, during the entire course of treatment, receive a total medication dose of 500 mg.

Drug Class
A group of drugs that share common properties, which may include a similar mechanism of action, chemical structure, or approved use. Antiretroviral (ARV) HIV drugs are classified into six drug classes on the basis of how each drug interferes with the HIV life cycle. These six classes include the nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), fusion inhibitors, CCR5 antagonists, and integrase strand transfer inhibitors (INSTIs).

Drug Interaction
A change in a drug’s effect on the body when taken with certain other drugs, supplements, or food, or when taken together with certain medical conditions. A drug interaction may cause the drug to be less effective, cause adverse effects, or increase the action of the drug. Potential drug interactions are considered when selecting antiretroviral (ARV) drugs to include in an HIV treatment regimen.

Drug Resistance
ALSO KNOWN AS: Resistance
When a bacteria, virus, or other microorganism mutates (changes form) and becomes insensitive to (resistant to) a drug that was previously effective. Drug resistance can be a cause of HIV treatment failure.

Drug-Drug Interaction
A change in a drug’s effect on the body when the drug is taken together with a second drug. A drug-drug interaction can delay, decrease, or enhance absorption of either drug. This can make either or both of the drugs less effective or more active, or cause adverse effects.

Drug-Food Interaction
A change in a drug’s effect on the body when the drug is taken together with certain foods or beverages. Not all drugs are affected by food, and some drugs are affected by only certain foods. A drug-food interaction can delay, decrease, or enhance absorption of a drug. This can cause the drug to be less effective, cause adverse effects, or increase the action of the drug.

Epidemic
A widespread outbreak of a disease in a large number of individuals over a particular period of time either in a given area or among a specific group of people.

Epidemiology
The study of the distribution, causes, and clinical characteristics of disease or health status in a population.

False Negative
A negative test result that incorrectly indicates that the condition being tested for is not present when, in fact, the condition is actually present. For example, a false negative HIV test indicates a person does not have HIV when, in fact, the person is infected with HIV.

False Positive
A positive test result that incorrectly indicates that the condition being tested for is present when, in fact, the condition is actually not present. For example, a false positive HIV test indicates a person has HIV when, in fact, the person is not infected with HIV.

Fixed-Dose Combination
Two or more drugs contained in a single dosage form, such as a capsule or tablet. An example of a fixed-dose combination HIV drug is Atripla (a combination of efavirenz, emtricitabine, and tenofovir). By reducing the number of pills a person must take each day, fixeddose combination drugs can help improve adherence to an HIV treatment regimen.

Generic Drug
A drug that has the same active ingredients, dosage, formulation, safety, strength, route of administration, quality, effectiveness, and intended use as a brand-name drug. For example, ibuprofen is a generic drug that has several manufacturers and brand names, including Advil and Motrin. Generic drugs are usually less expensive than brand-name drugs.

Genital Warts
ALSO KNOWN AS: Condyloma Acuminatum, Venereal Warts
A sexually transmitted infection caused by the human papillomavirus (HPV). Genital warts appear as raised pink or flesh-colored bumps on the surface of the vagina, cervix, tip of the penis, or anus.

Gonorrhea
A sexually transmitted infection caused by the bacterium Neisseria gonorrhoeae. Gonorrhea can also be transmitted from an infected mother to her child during delivery. Gonorrhea often has mild or no symptoms. However, if left untreated, gonorrhea can lead to infertility, and it can spread into the bloodstream and affect the joints, heart valves, and brain. Gonorrhea increases the risk of sexual transmission of HIV.

Hepatitis
Inflammation of the liver, usually from a viral infection. The most common hepatitis infections are hepatitis A, hepatitis B, and hepatitis C. Hepatitis may also be due to autoimmune disease, alcohol, medications, or toxic agents. Symptoms of hepatitis, if any, can include loss of appetite, nausea and vomiting, and jaundice. Hepatitis can lead to liver damage, liver failure, or cancer. Hepatitis is also often used to refer to the group of viral infections that affect the liver (hepatitis A, B, C, D, and E).

Hepatitis B Virus (HBV) Infection
Infection with the hepatitis B virus (HBV). HBV can be transmitted through blood, semen, or other body fluids during sex or injection-drug use. Because HIV and HBV share the same modes of transmission, people infected with HIV are often also coinfected with HBV. HBV infection progresses more rapidly in people coinfected with HIV than in people infected with HBV alone.

Hepatitis C Virus (HCV) Infection
Infection with the hepatitis C virus (HCV). HCV is usually transmitted through blood and rarely through other body fluids, such as semen. HCV infection progresses more rapidly in people coinfected with HIV than in people infected with HCV alone.

Herpes Simplex Virus 1 (HSV-1) Infection
An infection caused by herpes simplex virus 1 (HSV-1) and usually associated with lesions on the lips, mouth, and face. HSV-1 is very contagious and is transmitted by direct contact with someone who is infected (even if lesions are not visible). Treatment cannot completely clear HSV-1 from the body, but antiviral therapy can shorten and prevent outbreaks and reduce the risk of transmission. People with weakened immune systems, such as people with HIV, are more likely to have lesions that spread to other parts of the body than people with healthy immune systems.

Herpes Simplex Virus 2 (HSV-2) Infection
An infection caused by herpes simplex virus 2 (HSV-2) and usually associated with lesions in the genital or anal area. HSV-2 is very contagious and is transmitted by sexual contact with someone who is infected (even if lesions are not visible). Treatment cannot eradicate HSV-2 from the body, but antiviral therapy can shorten and prevent outbreaks and reduce the risk of transmission. People with weakened immune systems, such as people with HIV, are more likely to have lesions that spread to other parts of the body than people with healthy immune systems.

HIV Progression
The course of HIV infection. HIV is a chronic infection that progresses in four stages: acute HIV infection, asymptomatic HIV infection, symptomatic HIV infection, and AIDS. Antiretroviral therapy (ART) is designed to delay or stop the progression of HIV infection.

HIV-1
One of the two types of HIV, the virus that causes AIDS. AIDS is the most advanced stage of HIV infection. HIV-1 is transmitted through direct contact with HIV-infected body fluids, such as blood, semen, and genital secretions, or from an HIV-infected mother to her child during pregnancy, delivery, or breastfeeding (through breast milk). HIV-1 is responsible for the majority of HIV infections worldwide. In the United States, unless otherwise noted, the term “HIV” primarily refers to HIV-1.

HIV-2
One of the two types of HIV, the virus that causes AIDS. AIDS is the most advanced stage of HIV infection. HIV-2 infection is endemic to West Africa. Like HIV-1, HIV-2 is transmitted through direct contact with HIV-infected body fluids, such as blood, semen, and genital secretions, or from an HIV-infected mother to her child during pregnancy, delivery, or breastfeeding (through breast milk). HIV-2 infection generally takes longer to progress to symptomatic HIV/AIDS and has a lower mortality rate than HIV-1 infection.

Horizontal Transmission
Transmission of HIV, or other infectious disease, from one person to another, except from parent to child (vertical transmission). Horizontal transmission of HIV can occur during sex or needle sharing as the result of contact with the semen, vaginal fluid, or blood of an HIV-infected partner.

Human Immunodeficiency Virus (HIV)
The virus that causes AIDS, which is the most advanced stage of HIV infection. HIV is a retrovirus that occurs as two types: HIV-1 and HIV-2. Both types are transmitted through direct contact with HIV-infected body fluids, such as blood, semen, and genital secretions, or from an HIV-infected mother to her child during pregnancy, birth, or breastfeeding (through breast milk).

Human Papillomavirus (HPV)
The virus that causes human papillomavirus (HPV) infection, the most common sexually transmitted infection. There are two groups of HPV— types that can cause genital warts and types that can cause cancer. HPV is the most frequent cause of cervical cancer. In women with HIV, invasive cervical cancer is an AIDS-defining condition.

Immune System
A complex network of specialized cells, tissues, and organs that recognize and defend the body from foreign substances, primarily disease-causing microorganisms such as bacteria, viruses, parasites, and fungi. Organs and tissues of the immune system, called lymphoid organs, include the bone marrow, spleen, thymus, and tonsils. Immune system cells include white blood cells, such as B lymphocytes (B cells), T lymphocytes (T cells), dendritic cells, and macrophages. HIV infection gradually destroys the immune system.

Immunocompromised
When the body is unable to produce an adequate immune response. A person may be immunocompromised because of a disease or an infection, such as HIV, or as the result of treatment with drugs or radiation.

Immunodeficiency
Inability to produce an adequate immune response because of an insufficiency or absence of antibodies, immune cells, or both. Immunodeficiency disorders can be inherited, such as severe combined immunodeficiency; they can be acquired through infection, such as with HIV; or they can result from chemotherapy.

Immunosuppression
When the body’s ability to mount an immune response to fight infections or disease is reduced. Immunosuppression may result from certain diseases, such as HIV/AIDS, or as a result of radiotherapy or chemotherapy. Immunosuppression may also be deliberately induced by drugs used to prevent rejection of transplanted organs.

Incidence
The number of new cases of a disease in a specific area during a specific time period.

Infection
Invasion and growth of an infectious microorganism, such as a bacterium or virus, in the body. Infection can also refer to the disease caused by the infectious microorganism. For example, HIV infection is caused by the human immunodeficiency virus (HIV).

Infectious Disease
A disease that is caused by a microorganism, such as a bacterium, virus, or parasite, that is not normally found in the body and is capable of causing infection. Some, but not all, infectious diseases are contagious, meaning they can spread from person to person. Other infectious diseases can spread from animals or insects to humans, but not from person to person. HIV is both infectious and contagious.

Informed Consent
A communication process between a person and a health care provider or researcher to ensure that the person understands all relevant facts associated with a medical procedure or clinical trial. Before undergoing the procedure or participating in the trial, the person must sign an informed consent form that indicates understanding of the risks and benefits involved and of the risks and benefits of other options.

Injection Drug Use
A method of drug use. The drugs are injected directly into the body—into a vein, into a muscle, or under the skin—with a needle and syringe. Blood-borne viruses, including HIV and hepatitis, can be transmitted via shared needles or other drug injection equipment.

LGBTQ
Acronym for lesbian, gay, bisexual, transgender, and questioning.

Monotherapy
Using only one drug to treat an infection or disease. Currently, monotherapy for the treatment of HIV is not recommended outside of a clinical trial. The recommended treatment for HIV infection is combination antiretroviral therapy (ART), using a regimen that includes three or more antiretroviral (ARV) drugs from at least two different HIV drug classes.

Morbidity
Disease state or symptom. Morbidity rate is a measure of the frequency of occurrence of disease among a defined population during a specified time period.

Mortality
The state of being mortal (subject to death). Mortality rate is a measure of the frequency of occurrence of death among a defined population during a specified time period.

Mother-to-Child Transmission (MTCT)
ALSO KNOWN AS: Maternal-Child Transmission, Perinatal Transmission
When an HIV-infected mother passes HIV to her infant during pregnancy, labor and delivery, or breastfeeding (through breast milk). Antiretroviral (ARV) drugs are given to HIV-infected women during pregnancy and to their infants after birth to reduce the risk of mother-to-child transmission (MTCT) of HIV.

MSM
Acronym for men who have sex with men.

Off-Label Use
The legal, prescribed use of a drug in a manner different from that described on the Food and Drug Administration (FDA)-approved drug label. Off-label use can include using a drug for a different disease or medical condition or giving a drug at a different dose or via a different route of administration than approved by FDA.

Opportunistic Infection (OI)
An infection that occurs more frequently or is more severe in people with weakened immune systems, such as people with HIV or people receiving chemotherapy, than in people with healthy immune systems.

Palliative Care
Care to alleviate the physical and psychological symptoms of disease or the undesirable effects of treatment. The goal of palliative care is not to cure disease but to make the person more comfortable and improve the person’s quality of life. Palliative care may be given at any stage of a disease.

Pap Smear
ALSO KNOWN AS: Pap Test
A procedure in which cells and secretions are collected from inside and around the cervix for examination under a microscope. Pap smear also refers to the laboratory test used to detect any infected, potentially pre-cancerous, or cancerous cells in the cervical cells obtained from a Pap smear.

People Living with HIV/AIDS (PLWHA)
ALSO KNOWN AS: People Living with AIDS (PLWA), People Living with HIV (PLWH)
Infants, children, adolescents, and adults infected with HIV/AIDS.

Pill Burden
The number of tablets, capsules, or other dosage forms that a person takes on a regular basis. A high pill burden can make it difficult to adhere to an HIV treatment regimen.

Pneumonia
ALSO KNOWN AS: Bronchopneumonia
Inflammation of the lungs, which is usually caused by a bacterial, viral, or fungal infection. People older than 65 years of age or younger than 2 years of age and people with weakened immune systems are more at risk for pneumonia. Symptoms include cough, shortness of breath, fevers, chills, chest pain, and weakness. In people with HIV, recurrent pneumonia (pneumonia that returns again and again) is considered an AIDS-defining condition.

Post-Exposure Prophylaxis (PEP)
Short-term treatment started as soon as possible after high-risk exposure to an infectious agent, such as HIV, hepatitis B virus (HBV), or hepatitis C virus (HCV). The purpose of post-exposure prophylaxis (PEP) is to reduce the risk of infection. An example of a high-risk exposure is exposure to an infectious agent as the result of unprotected sex.

Pre-Exposure Prophylaxis (PrEP)
Administration of antiretroviral (ARV) drugs before potential HIV exposure in order to reduce the risk of HIV infection. Clinical trials are underway to determine if pre-exposure prophylaxis (PrEP) is a safe and effective way to reduce HIV transmission in people at high risk for HIV infection.

Protease Inhibitor (PI)
Antiretroviral (ARV) HIV drug class. Protease inhibitors (PIs) block protease (an HIV enzyme). This prevents new HIV from forming.

Rapid Test
A type of HIV antibody test used to screen for HIV infection. A rapid HIV antibody test can detect HIV antibodies in blood or oral fluid in less than 30 minutes. A positive rapid HIV antibody test must be confirmed by a second, different antibody test (a positive Western blot) for a person to be definitively diagnosed with HIV infection.

Receptor
A protein that is located inside or on the surface of a cell and that binds to a specific substance, such as a hormone, antigen, virus, or neurotransmitter. The binding of the substance to the cell receptor causes a change in the activity of the cell. In order to enter a host cell, HIV must first bind to receptors on the host cell.

Semen
ALSO KNOWN AS: Seminal Fluid
A thick, whitish fluid that is discharged from the male penis during ejaculation. Semen contains sperms and various secretions. HIV can be transmitted through the semen of a man with HIV.

Seroconversion
When an HIV-infected person converts from HIV negative to HIV positive by blood testing. Shortly after infection with HIV, the body begins to produce HIV antibodies. It takes the body a while to produce enough antibodies to be detected by an HIV antibody test—usually 10 to 14 days but sometimes up to 6 months. When HIV antibodies in the blood reach a detectable level, the HIV-infected person seroconverts. In other words, the person’s antibody test goes from HIV negative to HIV positive.

Sexual Transmission
Transmission of HIV, or other sexually transmitted infection, from one individual to another as the result of sexual contact.

Sexually Transmitted Infection (STI)
ALSO KNOWN AS: Sexually Transmitted Disease
An infectious disease that spreads from person to person during sexual contact. Sexually transmitted infections, such as syphilis, HIV infection, and gonorrhea, are caused by bacteria, parasites, and viruses.

Simian Immunodeficiency Virus (SIV)
An HIV-like virus that can infect monkeys and apes and can cause a disease similar to AIDS. Because HIV and simian immunodeficiency virus (SIV) are closely related viruses, researchers study SIV as a way to learn more about HIV. However, SIV cannot infect humans, and HIV cannot infect monkeys.

Sperm Washing
A laboratory procedure that involves “washing” semen from an HIV-infected man to separate the sperm from the fluid part of the semen. Because the seminal fluid contains the highest concentration of HIV, the “washed” sperm should not contain any HIV. Sperm washing can be considered as a reproductive option for an HIV discordant couple in which the man is the HIV-infected partner. Because sperm washing has not been proven completely effective, couples using the procedure should be counseled regarding the potential risks for transmission of HIV.

Spermicide
A topical preparation or substance used during sexual intercourse to kill sperm. Although spermicides may prevent pregnancy, they do not protect against HIV infection or other sexually transmitted infections. Irritation of the vagina and rectum that sometimes occurs with use of spermicides may increase the risk of sexual transmission of HIV.

Symptomatic HIV Infection
Stage of HIV infection during which signs or symptoms of the infection begin to appear. The onset of symptoms signals the transition from asymptomatic HIV infection to AIDS.

Syphilis
An infectious disease caused by the bacterium Treponema pallidum, which is typically transmitted through direct contact with a syphilis sore, usually during vaginal or oral sex. Syphilis can also be transmitted from an infected mother to her child during pregnancy. Syphilis sores occur mainly on the genitals, anus, and rectum, but also on the lips and mouth. Genital sores (chancres) caused by syphilis increase the risk of sexual transmission of HIV.

T Lymphocyte
ALSO KNOWN AS: T Cell
A type of lymphocyte. There are two major types of T lymphocytes: CD8 cells (cytotoxic T lymphocytes) and CD4 cells (helper T lymphocytes); both T cell types are essential for a healthy immune system. HIV infects and destroys CD4 cells, gradually destroying the immune system.

Tolerance
The ability to tolerate a drug when given as prescribed. In other words, tolerance means benefiting from the drug without having any adverse effects that would make it impossible to continue taking the drug.

Toxicity
ALSO KNOWN AS: Drug Toxicity
The extent to which a drug causes adverse effects. Drug toxicity is one of the factors considered when selecting antiretroviral (ARV) drugs to include in an HIV treatment regimen.

Treatment Failure
When an antiretroviral (ARV) regimen is unable to control HIV infection. Treatment failure can be clinical failure, immunologic failure, virologic failure, or any combination of the three. Factors that can contribute to treatment failure include drug resistance, drug toxicity, or poor treatment adherence.

Treatment Regimen
ALSO KNOWN AS: Regimen
A structured treatment plan designed to improve and maintain health. Recommended HIV treatment regimens include a combination of three or more antiretroviral (ARV) drugs from at least two different drug classes.

Tuberculosis (TB)
An infection caused by the bacteria Mycobacterium tuberculosis and Mycobacterium bovis. Tuberculosis (TB), also referred to as Mycobacterium infection, is spread when a person with an active infection (TB disease) coughs, sneezes, speaks, or sings, and then a person nearby breathes in the bacteria. TB usually affects the lungs, but it can also affect other parts of the body, such as the kidneys, spine, and brain. There are two forms of TB: latent TB infection and TB disease. In people with HIV, TB is considered an AIDS-defining condition.

Undetectable Viral Load
When the amount of HIV in the blood is too low to be detected with a viral load (HIV RNA) test. Antiretroviral (ARV) drugs may reduce a person’s viral load to an undetectable level; however, that does not mean the person is cured. Some HIV, in the form of latent HIV reservoirs, remain inside cells and in body tissues.

Vertical Transmission
Vertical transmission of HIV refers to HIV transmission from an HIVinfected mother to her child during pregnancy, labor and delivery, or breastfeeding (through breastmilk).

Viral Load (VL)
The amount of HIV in a sample of blood. Viral load (VL) is reported as the number of HIV RNA copies per milliliter of blood. An important goal of antiretroviral therapy (ART) is to suppress a person’s VL to an undetectable level—a level too low for the virus to be detected by a VL test.

Viral Suppression
ALSO KNOWN AS: Virologic Control
When antiretroviral therapy (ART) reduces a person’s viral load (HIV RNA) to an undetectable level. Viral suppression does not mean a person is cured; HIV still remains in the body. If ART is discontinued, the person’s viral load will likely return to a detectable level.

Virus
A microscopic infectious agent that requires a living host cell in order to replicate. Viruses often cause disease in humans, including measles, mumps, rubella, polio, influenza, and the common cold. HIV is the virus that causes AIDS.

Window Period
The time period from infection with HIV until the body produces enough HIV antibodies to be detected by an HIV antibody test. This generally takes 2 to 8 weeks, but in some people it can take up to 6 months. During the window period, a person can have a negative result on an HIV antibody test despite being infected with HIV.

World Health Organization (WHO)
The agency of the United Nations that provides global leadership on health-related matters. Responsibilities of the World Health Organization (WHO) include shaping the global health research agenda, setting health standards, promoting evidence-based policy options, providing technical support to countries, and monitoring and assessing health trends.

Abbreviations and Acronyms:

AIDS Acquired Immunodeficiency Syndrome

ART Antiretroviral Therapy

ARV Antiretroviral

ASO AIDS Service Organization

BID Twice a Day

DNA Deoxyribonucleic Acid

HBV Hepatitis B Virus

HCV Hepatitis C Virus

HIV Human Immunodeficiency Virus

HPV Human Papillomavirus

HSV-1 Herpes Simplex Virus 1

HSV-2 Herpes Simplex Virus 2

IV Intravenous

LGBTQ Lesbian Gay Bisexual Transgender Questioning

MSM Men Who Have Sex With Men

PEP Post-Exposure Prophylaxis

PLWHA People Living with HIV/AIDS

PrEP Pre-Exposure Prophylaxis

QD Once a Day

QID Four Times a Day

RNA Ribonucleic Acid

SIV Simian Immunodeficiency Virus

STI Sexually Transmitted Infection

TB Tuberculosis

TID Three Times a Day

VL Viral Load

WHO World Health Organization