HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immune deficiency syndrome).
The virus can be found in certain fluids in the bodies of people who have HIV, including blood, semen, anal and vaginal fluids, and breast milk.
HIV can enter a person’s bloodstream through tiny tears in the anus, rectum, vagina, penis or mouth, or through open sores like those caused by herpes or syphilis.
A person’s chance of getting HIV depends on:
HIV can enter a person’s bloodstream when they share a syringe or other injection equipment with someone who has HIV. Always use your own syringes (PDF) and other equipment.
HIV can spread during childbirth or breastfeeding. To protect your baby, get an HIV test before you give birth, and start or stay on treatment if you have HIV.
Other body fluids and waste — like saliva, sweat, tears, urine, and feces — do not contain enough virus to transmit HIV. You cannot get HIV through hugging, kissing, coughing, shaking hands, or sharing a toilet or drinking fountain.
It takes a few days for an HIV infection to develop in a person’s body. If you may have been exposed to HIV in the past 72 hours, take emergency PEP to prevent a new HIV infection.
In the first few weeks after infection, people with HIV have a high level of virus in their bodies and can easily pass HIV to others. As the virus multiplies, some people develop flu-like symptoms including fever, swollen glands, aches and pains. If you experience symptoms or may recently have been exposed to HIV, avoid having sex and go to a clinic or hospital and ask to be tested for acute HIV infection.
Most people show few symptoms for years after they get HIV. They may look and feel healthy, but without treatment HIV will slowly damage their body and can spread to other people. To protect yourself and others, get regularly tested for HIV and start treatment right away if you have HIV.
If not treated, HIV destroys CD4 cells (or “T cells”) — an important part of the body’s immune system. If HIV destroys enough CD4 cells, rare cancers and infections begin to attack the body. This stage is called AIDS. To prevent AIDS, get tested and treated for HIV.