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What is HIV/AIDS?

What is HIV?

HIV stands for human immunodeficiency virus. Unlike some other viruses, the human body cannot get rid of HIV. This means that someone with HIV will have it for life. HIV works by attacking the immune system–specifically CD4 cells, or T cells–which help the immune system fight off infections and diseases. If left untreated, HIV will destroy CD4 cells in the body, making the person more likely to get opportunistic infections and/or other illnesses. Once this occurs, the opportunistic infections take advantage of a weak immune system, signaling that the person has transitioned from HIV positive status into AIDS.

What is AIDS?

AIDS stands for acquired immunodeficiency syndrome and is the final stage of HIV infection. Not everyone who has HIV will advance to AIDS. AIDS is the stage of infection that occurs when someone with an HIV-impaired immune system is badly damaged, making the body vulnerable to opportunistic infection. When the number of CD4 or T-cells falls below 200 cells per millimeter of blood, someone is considered to have progressed to the AIDS stage. (Healthy CD4 counts are between 500 and 1,600 cells per millimeter of blood.) Someone also can be diagnosed with AIDS if they develop one or more opportunistic infections, regardless of CD4 count. Without treatment, people with HIV typically survive about 3 years. People with AIDS need medical treatment to prevent death.

If I have HIV, will I develop AIDS?

HIV is a manageable disease, and with proper medical care it can be controlled. HIV is treated using a combination of medicines to fight HIV infection called antiretroviral therapy or ART. ART is not a cure for HIV. If taken as prescribed by a doctor, it can control HIV so you may live a longer and healthier life. ART involves taking a combination of HIV medications every day, exactly as prescribed. These medications prevent HIV from making copies of itself, which reduces the amount of HIV in your body. Having less HIV in your body gives the immune system a chance to recover and fight off infections, which greatly increases your life expectancy to that of someone who is not infected with HIV. By reducing the amount of HIV in your body, HIV medications also reduce the risk of transmitting the virus to others. ART is recommended for all people living with HIV, regardless of how long they have had the virus or how healthy they are. If left untreated, HIV will attack the immune system, eventually progressing to AIDS and shortening life expectancy.

How is HIV transmitted?

HIV is transmitted through specific activities or behaviors. The most common ways are through sexual behaviors and needle or syringe use. HIV is not spread easily, and only certain body fluids from an infected person can transmit HIV. These fluids are:

  • blood
  • semen
  • pre-seminal fluid (pre-cum)
  • rectal fluids
  • vaginal fluids
  • breast milk

For HIV to be transmitted, one or more of these fluids must come in contact with a mucous membrane – found inside the rectum, vagina, penis, and mouth – or be directly injected into the bloodstream, such as by sharing a needle or syringe.

In the United States, HIV is spread mainly by:

  • Having anal or vaginal sex with someone who has HIV without a condom or taking medication to prevent or treat HIV
  • Anal sex is the highest-risk sexual behavior and the person receiving anal sex is more at-risk
  • Vaginal sex is the second-highest sexual risk behavior
  • Sharing needles or syringes, rinse water, or other equipment (works) used to inject drugs (legal or illegal substances) with someone who has HIV. HIV can live in a used needle for up to 42 days, depending on temperature and other factors.

Less common ways HIV is spread:

  • Mother-to-child during pregnancy, birth, or breast feeding. Although the risk can be high if the mother has HIV and is not taking medications (ART), recommendations to test all pregnant women for HIV and start HIV treatment immediately for those who test positive lowers the number of babies who are born with HIV.
  • Being stuck with an HIV-contaminated needle or sharp. This is a risk primarily for health care workers.

HIV is a weak virus and does not survive long outside the body (such as on surfaces), and it cannot reproduce outside of the human body. HIV is not spread by:

  • Air or water
  • Mosquitoes, ticks, or other insects
  • Saliva, tears, sweat, feces, vomit, urine, mucus that is not mixed with blood of an infected person
  • Casual contact such as shaking hands, hugging, sharing toilets or dishes/drinking glasses/utensils, or closed-mouth or “social” kissing with someone who is HIV positive
  • Drinking fountains
  • Other sexual activities that do not involve the exchange of body fluids (i.e. touching)

Should I get tested?

Testing for HIV is the only way to know for sure if you have HIV. Many people do not have any symptoms and can live for many years without knowing they are infected. By not knowing, people may develop infections and illness due to a weakened immune system, develop AIDS, and/or pass HIV to others through certain activities or behaviors.

The Centers for Disease Control and Prevention (CDC) recommends everyone 13 to 64 years old get tested for HIV at least once and people at a higher risk for infection should get tested more often. Factors that increase the risk of HIV infection include:

  • Having vaginal or anal sex without a condom with someone who has HIV or whose HIV status you do not know
  • Being a man who has had sex with another man
  • Injecting drugs and sharing needles, syringes, or other drug equipment (works) with others
  • Exchanging sex for money or drugs
  • Being diagnosed or sought treatment for another sexually transmitted disease (STD)
  • Being diagnosed or sought treatment for hepatitis or tuberculosis (TB)
  • Having sex with anyone who has any of the above HIV risk factors or whose sexual history you do not know.