Common HIV/AIDS Terms

Please attend our FREE events during AIDS Education Month to learn more about HIV/AIDS.

Contact the AIDS Library for additional support in expanding your HIV/AIDS knowledge.


AIDS (Acquired Immune Deficiency Syndrome): A CD4 count of 200 or below or a diagnosis of an opportunistic infection (OI) from the CDC list. Learn More

Antibody: Proteins in the blood that find “invaders” such as bacteria or viruses in the body and attack. Learn More

CD4 Cells (Immune System Cells): These cells are also called T cells. They are the immune systems natural response to viruses and bacteria. Learn More

Co-infection: Infection with more than one disease at the same time. Learn More

Harm Reduction: A public health method that gives individuals knowledge on how to reduce the level of risk when engaging in risky behavior. When thinking about HIV and harm reduction, needle exchange programs have been successful in reducing transmission rates. Learn about Philadelphia’s needle exchange program.

HIV (Human Immunodeficiency Virus): A virus that weakens the immune system over time. Learn More

Opportunistic Infection (OI): An infection that occurs in people with weakened immune systems, such as people with HIV. Learn More

Serodiscordant: A relationship between an HIV positive person and an HIV negative person. Learn More

Treatment Adherence: Taking HIV medication exactly as prescribed. Learn More

Viral Load: The amount of active HIV in a person’s blood. Learn More


AACO: (AIDS Activities Coordinating Office) This is the Philadelphia area’s grantee that distributes federal and state funds for HIV/AIDS services. It is administered by the Philadelphia Department of Health. Learn more

ACT UP: (AIDS Coalition to Unleash Power)This is an activist organization for those infected and affected by HIV/AIDS with chapters internationally. Learn more about Philadelphia’s Chapter.

ADAP: (AIDS Drug Assistance Program) A Federal program that helps pay for HIV medications. In Pennsylvania, it is called SPBP, Special Pharmaceutical Benefits Program. Learn More

AEM: (AIDS Education Month) For the past 19 years, Philadelphia FIGHT has hosted AEM, a series of events throughout Philadelphia to increase awareness of HIV/AIDS and to bring people together to find strategies to combat the virus. Learn More

ARVs/ART: (Antiretroviral Drugs/Therapy) There are over 30 antiretroviral medication approved by the Food and Drug Administration (FDA). Antiretroviral therapy consists of giving a person a combination of two or more antiretroviral drugs to treat HIV/AIDS. Learn More

CDC: (Centers for Disease Control) A government organization whose mission is to create the expertise, information, and tools that people and communities need to protect their health. Learn More

HCV: (Hepatitis C Virus) One of a group of viruses which can lead to inflammation of the liver. Learn More

IDU: (Injection Drug Users) The World Health Organization (WHO) estimates that, one in every ten new HIV infections are among Injection Drug Users in the United States. Learn More

LGBTQ: Lesbian, gay, bisexual, trans-gender or questioning. Learn More

PEP: (Post-Exposure Prophylaxis) Taking anti-HIV drugs as soon as you may have been exposed to HIV can reduce the chance of you becoming HIV positive. Learn More

(Philadelphia) FIGHT: Field Initiating Group for HIV Trails. Learn More

PLWA: (People living with AIDS) The CDC estimates that the number of people diagnosed with AIDS in the United States was 32,052 in the year 2011. Learn More

PLWH: (People living with HIV) The CDC estimates that more than 1.1 million people in the United States are living with HIV infection, and almost 1 in 5 (18.1%) are unaware of their infection. Learn More

PrEP: (Pre-Exposure Prophylaxis) A new HIV prevention method in which people who do not have HIV take a daily pill to reduce their risk of becoming infected. Learn more

YMSM: Young men who have sex with men. Learn More