HIV (NIH Forum December 2013)


HIV stands for human immunodeficiency virus. It is the virus that can lead to acquired immunodeficiency syndrome, or AIDS. Unlike some other viruses, the human body cannot get rid of HIV. That means that once you have HIV, you have it for life.

Scientists identified a type of chimpanzee in West Africa as the source of HIV infection in humans. They believe that the chimpanzee version of the immunodeficiency virus (called simian immunodeficiency virus, or SIV) most likely was transmitted to humans and mutated into HIV when humans hunted these chimpanzees for meat and came into contact with their infected blood. Studies show that HIV may have jumped from apes to humans as far back as the late 1800s. Over decades, the virus slowly spread across Africa and later into other parts of the world. We know that the virus has existed in the United States since at least the mid- to late 1970s.

No safe and effective cure currently exists, but scientists are working hard to find one, and remain hopeful. Meanwhile, with proper medical care, HIV can be controlled. Treatment for HIV is often called antiretroviral therapy or ART. It can dramatically prolong the lives of many people infected with HIV and lower their chance of infecting others. Before the introduction of ART in the mid-1990s, people with HIV could progress to AIDS in just a few years. Today, someone diagnosed with HIV and treated before the disease is far advanced can have a nearly normal life expectancy.

HIV affects specific cells of the immune system, called CD4 cells, or T cells. Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. When this happens, HIV infection leads to AIDS.


Mode of Transmission:


Only certain fluids—blood, semen (cum), pre-seminal fluid (pre-cum), rectal fluids, vaginal fluids, and breast milk—from an HIV-infected person can transmit HIV. These fluids must come in contact with a mucous membrane or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to possibly occur. Mucous membranes can be found inside the rectum, the vagina, the opening of the penis, and the mouth.

HIV is spread mainly by

  • Having unprotected sex (sex without a condom) with someone who has HIV.
    • Anal sex is the highest-risk sexual behavior. Receptive anal sex (bottoming) is riskier than insertive anal sex (topping).
    • Vaginal sex is the second highest-risk sexual behavior.
    • Having multiple sex partners or having other sexually transmitted infections can increase the risk of infection through sex.
  • Sharing needles, syringes, rinse water, or other equipment (works) used to prepare injection drugs with someone who has HIV.


Less commonly, HIV may be spread by

  • Being born to an infected mother. HIV can be passed from mother to child during pregnancy, birth, or breastfeeding.
  • Being stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers.
  • Receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV. This risk is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.
  • Eating food that has been pre-chewed by an HIV-infected person. The contamination occurs when infected blood from a caregiver’s mouth mixes with food while chewing, and is very rare.
  • Being bitten by a person with HIV. Each of the very small number of documented cases has involved severe trauma with extensive tissue damage and the presence of blood. There is no risk of transmission if the skin is not broken.
  • Oral sex—using the mouth to stimulate the penis, vagina, or anus (fellatio, cunnilingus, and rimming). Giving fellatio (mouth to penis oral sex) and having the person ejaculate (cum) in your mouth is riskier than other types of oral sex.
  • Contact between broken skin, wounds, or mucous membranes and HIV-infected blood or blood-contaminated body fluids. These reports have also been extremely rare.
  • Deep, open-mouth kissing if the person with HIV has sores or bleeding gums and blood is exchanged. HIV is not spread through saliva. Transmission through kissing alone is extremely rare.



The only way to know if you are infected with HIV is to be tested. You cannot rely on symptoms to know whether you have HIV. Many people who are infected with HIV do not have any symptoms at all for 10 years or more. Some people who are infected with HIV report having flu-like symptoms (often described as “the worst flu ever”) 2 to 4 weeks after exposure. Symptoms can include:

  • Fever
  • Enlarged lymph nodes
  • Sore throat
  • Rash


These symptoms can last anywhere from a few days to several weeks. During this time, HIV infection may not show up on an HIV test, but people who have it are highly infectious and can spread the infection to others. However, you should not assume you have HIV if you have any of these symptoms. Each of these symptoms can be caused by other illnesses. Again, the only way to determine whether you are infected is to be tested for HIV infection.




Anybody can get HIV, but you can take steps to protect yourself from HIV infection.

  • Don’t have sex. Abstinence (not having sex of any kind) is a sure way to avoid HIV infection through sexual contact.
  • Get tested and know your partner’s HIV status. Talk to your partner about HIV testing and get tested before you have sex.
  • Be faithful to your partner. If you and your partner are both HIV negative and have sex only with each other, you are not at risk of HIV infection through sexual contact.
  • Use condoms. Use a condom every time you have vaginal, anal, or oral sex. 
  • Limit your number of sexual partners. If you have more than one sexual partner, get tested for HIV regularly. Get tested and treated for sexually transmitted infections (STIs), and insist that your partners do, too. Having an STI can increase your risk of becoming infected with HIV.
  • Don’t inject drugs. But if you do, use only clean needles and equipment and don’t share your equipment with others.