Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome, also known as AIDS. HIV kills or damages the cells of the body’s immune system, destroying CD4 positive (CD4+) T cells, a type of white blood cell vital to fighting off infection. Because HIV compromises the immune systems, HIV-positive people are vulnerable to other infections, diseases, and complications. A blood test is used to confirm the presence of HIV in the body.
AIDS is the final stage of HIV infection. A person infected with HIV is diagnosed with AIDS when he or she has one or more opportunistic infections, such as pneumonia or tuberculosis, and has a dangerously low number of CD4+ T cells (less than 200 cells per cubic millimeter of blood).
HIV is most often transmitted through unprotected sex with an infected person. AIDS may also spread by sharing drug needles or through contact with the blood of an infected person. Women with HIV can transmit it to their babies before or during birth or through breastfeeding. HIV-infected people taking antiretroviral therapy can still infect others through unprotected sex and needle-sharing.
Incapable of surviving long outside the body, HIV cannot be transmitted through routine daily activities, such as using a toilet seat, sharing food utensils or drinking glasses, shaking hands, or kissing. The virus can only be transmitted from person to person, not through animals or insect bites.
The Centers for Disease Control and Prevention (CDC) estimates more than 1 million people are living with HIV in the United States. Twenty-one percent of people living with HIV—one in five—are unaware of their infection. According to CDC statistics, an estimated 56,300 Americans become infected with HIV each year. The World Health Organization’s latest figures pinpoint the total number of people living with HIV/AIDS worldwide at 33.3 million.
There is no cure for HIV/AIDS. Before the development of certain medications, people with HIV could progress to AIDS in just a few years. Today, many effective medicines allow infected people to live much longer—even decades—with HIV before developing AIDS. Most of these medicines “inhibit” the progress of the disease by interfering with the virus’s reproduction, protein production, and ability to enter the body’s cells.