WHAT IS HIV?
HIV stands for human immunodeficiency virus. It is the virus that can lead to acquired immunodeficiency syndrome, or AIDS, if not treated. Unlike some other viruses, the human body can’t get rid of HIV completely, even with treatment. So once you get HIV, you have it for life.
HIV attacks the body’s immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections. Untreated, HIV reduces the number of CD4 cells (T cells) in the body, making the person more likely to get other infections or infection-related cancers. Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last stage of HIV infection.
WHAT IS AIDS?
AIDS is the most severe phase of HIV infection. AIDS stands for Acquired Immune Deficiency Syndrome.
This is the stage of HIV infection that occurs when your immune system is badly damaged and you become vulnerable to opportunistic infections. When the number of your CD4 cells falls below 200 cells per cubic millimeter of blood (200 cells/mm3), you are considered to have progressed to AIDS. (In someone with a healthy immune system, CD4 counts are between 500 and 1,600 cells/mm3.) You are also considered to have progressed to AIDS if you develop one or more opportunistic illnesses, regardless of your CD4 count.
IS THERE A CURE FOR HIV?
No effective cure currently exists for HIV. But with proper medical care, HIV can be controlled. Treatment for HIV is called antiretroviral therapy or ART. If taken the right way, every day, ART can dramatically prolong the lives of many people infected with HIV, keep them healthy, and greatly lower their chance of infecting others. Before the introduction of ART in the mid-1990s, people with HIV could progress to AIDS (the last stage of HIV infection) in a few years. Today, someone diagnosed with HIV and treated before the disease is far advanced can live nearly as long as someone who does not have HIV.
Learn about how to protect yourself, and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
HOW IS HIV TRANSMITTED?
You can get or transmit HIV only through specific activities. Most commonly, people get or transmit HIV through sexual behaviors and needle or syringe use.
Only certain body fluids—blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk—from a person who has HIV 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 occur. Mucous membranes are found inside the rectum, vagina, penis, and mouth.
In the United States, HIV is spread mainly by
- Having anal or vaginal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV.
- For the HIV-negative partner, receptive anal sex (bottoming) is the highest-risk sexual behavior, but you can also get HIV from insertive anal sex (topping).
- Either partner can get HIV through vaginal sex, though it is less risky for getting HIV than receptive anal sex.
- Sharing needles or syringes, rinse water, or other equipment (works) used to prepare drugs for injection with someone who has HIV. HIV can live in a used needle up to 42 days depending on temperature and other factors.
Less commonly, HIV may be spread
- From mother to child during pregnancy, birth, or breastfeeding. Although the risk can be high if a mother is living with HIV and not taking medicine, recommendations to test all pregnant women for HIV and start HIV treatment immediately have lowered the number of babies who are born with HIV.
- By being stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers.
CAN I GET HIV FROM CASUAL CONTACT, USING A PUBLIC SPACE, OR FROM A MOSQUITO BITE?
No. HIV is NOT transmitted:
- By hugging, shaking hands, sharing toilets, sharing dishes, or closed-mouth or “social” kissing with someone who is HIV-positive.
- Through saliva, tears, or sweat that is not mixed with the blood of an HIV-positive person.
- By mosquitoes, ticks or other blood-sucking insects.
- Through the air.
As noted above, only certain body fluids—blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk—from an HIV-infected person can transmit HIV. Most commonly, people get or transmit HIV through sexual behaviors and needle or syringe use. Babies can also get HIV from an HIV-positive mother during pregnancy, birth, or breastfeeding.
HOW CAN I PROTECT MYSELF, MY PARTNER, OR MY PATIENTS?
If you’re HIV-negative:
- Get a free, confidential HIV test. Visit gettested.cdc.gov to find a testing location. Make sure you know your partner’s status, too — before you have sex.
- Practice safe sex. Use condoms every time you have sex.
- Talk to your doctor about pre-exposure prophylaxis (PrEP) if you have an HIV-positive partner. PrEP is a daily pill that can reduce your risk of getting HIV from sex by more than 90%.
- Visit a doctor right away if you think you may have been exposed to HIV. The doctor may decide that you should get post-exposure prophylaxis, also known as PEP. PEP is an anti-HIV medicine that may lower your chances of getting HIV after you have been exposed to the virus.
If you’re HIV-positive:
- Take care of your health and visit your doctor regularly.
- Aim to achieve and maintain an undetectable viral load by taking your medication as prescribed and for at least 6 months. Having an undetectable viral load means that you are much less likely to transmit HIV to a partner.
- Educate your partner about PrEP and PEP, if they are HIV-negative.
If you’re a health care professional:
- Know the HIV screening recommendations and implement them, as appropriate.
- Talk to your patients about their HIV risk and how to practice safe sex.
- Know when to recommend PrEP and PEP to HIV-negative patients.
- Work closely with HIV-positive patients to encourage them to stay healthy and help them adhere to their treatment. Also, if they’re sexually active, educate them about PrEP and PEP.
Learn about how to protect yourself, and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
HOW DO I KNOW IF I AM HIV POSITIVE?
The only way to know for sure whether you have HIV is to get tested. CDC recommends that everyone between the ages of 13 and 64 get tested for HIV at least once as part of routine health care. Knowing your HIV status gives you powerful information to help you take steps to keep you and your partner(s) healthy. About 1 in 7 people in the United States who have HIV do not know they have it.
WHERE CAN I GET TESTED?
You can ask your health care provider for an HIV test. Many medical clinics, substance abuse programs, community health centers, and hospitals offer them too. You can also find a testing site near you by:
- Calling 211
- calling 1-800-CDC-INFO (232-4636),
- visiting gettested.cdc.gov or locator.hiv.gov
- texting your ZIP code to KNOW IT (566948).
- You can also buy a home testing kit at a pharmacy or online.