HIV stands for Human Immunodeficiency Virus. It is the virus that causes AIDS. AIDS stands for Acquired Immune Deficiency Syndrome. HIV can be transmitted through the blood, sexual fluids, or breast milk of an HIV-infected person.
Over time, infection with HIV can weaken the immune system to the point that the system has difficulty fighting off certain infections. These types of infections are known as opportunistic infections. These infections are usually controlled by a healthy immune system, but they can cause problems or even be life-threatening in someone with AIDS.
A blood test can determine if a person is infected with HIV. Too many people don’t know they have HIV. In the United States, nearly 1.1 million people are living with HIV, and almost one in five don’t know they are infected. Getting tested is the first step to finding out if you have HIV. If you have HIV, getting medical care and taking medicines regularly helps you live a longer, healthier life and also lowers the chances of passing HIV on to others.
If a person tests positive for HIV, it does not necessarily mean that the person has AIDS. A diagnosis of AIDS is made by a physician according to the CDC AIDS Case Definition. A person infected with HIV may receive an AIDS diagnosis after developing one of the CDC-defined AIDS indicator illnesses. A person with HIV can also receive an AIDS diagnosis on the basis of certain blood tests (CD4 counts) and may not have experienced any serious illnesses.
Since 1996, the introduction of powerful anti-retroviral therapies has dramatically changed the progression time between HIV infection and the development of AIDS. There are also other medical treatments that can prevent or cure some of the illnesses associated with AIDS, though the treatments do not cure AIDS itself. Because of these advances in drug therapies and other medical treatments, estimates of how many people will develop AIDS and how soon are being recalculated, revised, or are currently under study.
The Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates that, since the beginning of the epidemic, almost 60 million people worldwide have been infected with HIV and 25 million people have died of HIV-related causes. UNAIDS estimates that about 33.4 million people worldwide were living with HIV in 2008.
- Unprotected vaginal, anal, or oral sex
- Early age of first sexual activity—It is common for youth to engage in sexual activity before receiving information about HIV prevention
- Heterosexual sex–Women and minorities are particularly vulnerable to HIV infection
- Men who have Sex with Men (MSM)–Stigma and discrimination make it more difficult for MSM to access testing and counseling services
- Sexually transmitted infection (STIs)–The presence of other STIs can greatly increase the likelihood of HIV transmission
- Unprotected vaginal, anal, or oral sex
- Exchange sex for money
- Substance abuse—Chronic and intermittent substance users are more likely to engage in high-risk behaviors while using. Injection drug users also run the risk of being infected by HIV while sharing unclean needles.
- Poverty—Socioeconomic factors can directly and indirectly influence a person’s vulnerability to HIV infection. For many people poverty prevents access to quality health care.
- Out-of-school youth—Those that drop out of school are more likely to become sexually active younger and less likely to use condoms and other types of contraception.
- Lack of awareness—Many people, particularly youth, don’t recognize the ways in which they are vulnerable to HIV infection, making them more likely to behave in ways that put them at risk.
The risk of transmission varies with the type of exposure (e.g. sexual, needle sharing, etc.) The Centers for Disease Control and Prevention offers a table quantifying the this HIV transmission risk that comes from different types of exposures. See the table and explanation at the CDC website.
While not having sex or to having sex with a long-term mutually monogamous partner who is not infected with HIV or other sexually transmitted infections (STIs) is the only way to protect yourself completely, latex condoms used consistently and correctly are highly effective in preventing HIV and many other STIs.