In 1981, clusters of gay men in Los Angeles and New York succumbed to opportunistic infections including an uncommon bacteria known as Pneumocystis carinii (now Pneumocystis jiroveci). Initially the syndrome was called GRID (Gay-Related Immunodeficiency Disease) because it was thought to only affect gay men. Then, people with hemophilia started to die.

As the disease expanded to populations beyond gay men the name Acquired Immune Deficiency Syndrome or AIDS was adopted. The Acquired Immune Deficiency Syndrome (AIDS) epidemic in the U.S. is now more than three decades old. The cumulative estimated number of AIDS diagnoses through 2010 in the United States was 1,155,792. The cumulative estimated number of deaths of persons with an AIDS diagnosis in the United States, through 2010, was 636,048.

In 1984, Human immunodeficiency virus (HIV) was identified as the cause of AIDS. The CDC currently estimates that more than a million Americans aged 13 years and older are living with HIV infection, including 180,900 (15.8%) who are unaware of their infection. The number of new HIV infections (incidence) in the U.S. remains stable at about 50,000 per year. In 2011, an estimated 49,273 people were diagnosed with HIV infection in the United States. In that same year, an estimated 32,052 people were diagnosed with AIDS.

CDC estimated a transmission rate of about 5 per 100 persons living with HIV infection in the United States in 2006, meaning that 95% of those infected did not transmit HIV. This is an 89% decline in the estimated rate of transmission since the peak of the epidemic in the mid-1980s. The decline is likely due to prevention efforts and availability of improved testing and treatment.

HIV transmission risk varies by mode of transmission. Excluding infected blood transfusion, needle-sharing during injection drug use has the highest risk per exposure. The most common transmission mode is unprotected receptive anal intercourse. Certain populations including men who have sex with men (MSM), blacks/African Americans, and Hispanic/Latinos are the groups most affected by HIV infection. Geographically, urban areas are the most heavily impacted.

HIV transmission is preventable. Effective prevention strategies including:

1. Routine HIV testing and counseling including risk assessment
2. Comprehensive STD assessment, counseling and treatment including early HIV antiretroviral therapy
3. Abstinence
4. Mutual monogamy
5. Condoms
6. Clean needle/syringe exchange
7. Male circumcision
8. Comprehensive sex education

Unfortunately the most practical prevention strategies have often met with ideological and funding impediments. In the previous decade a significant portion of funding and attention was focused on potential public health challenges, i.e. bioterrorism, pandemic influenza, etc. Actual public health emergencies like chronic disease, environmental hazards and STDs took budget cuts. In addition, the economic recession is impacting prevention efforts at the state and local levels.

Prior to 1/1/2014 about 30% of HIV⁺ Americans were uninsured. In those states that have opted to expand medicaid, all healthcare not just AIDS/HIV treatments will be covered for about 60% of the uninsured HIV⁺population. Political posturing may yet impede full implementation so the outcome remains uncertain.