What is HIV?

Human immunodeficiency virus (HIV) is the virus, or germ, that causes acquired immune deficiency syndrome (AIDS). The virus weakens a person's ability to fight infections and cancer by infecting and killing CD4 cells (also called T cells).

Having HIV does not always mean you have AIDS. It can take many years for people with the virus to develop AIDS. There is no cure for HIV or for AIDS. People with HIV are said to have AIDS when their T cells are very low and/or they develop certain infections or cancers.

How many people have HIV in the United States?

There are about 1.1 million people with HIV in the United States today, with new cases averaging about 38,000 per year. About 14% of the people with HIV, or one in 7 people, do not know that they have the virus. Anyone can get HIV, but certain things increase your risk.

Symptoms and Causes

How do people get HIV?

You can get HIV when body fluids from an infected person enter your bloodstream. Body fluids are blood, semen, vaginal fluids, fluids from the anus, and breast milk.

The virus can enter the blood through linings in the mouth, anus, or sex organs (the penis and vagina), or through broken skin. Both men and women can spread HIV.

You can have HIV and feel okay and still give the virus to others. Pregnant women with HIV can also give the virus to their babies.

The most common ways that people get HIV are having sex with an infected person and sharing a needle to take drugs.

You cannot get HIV from:

  • Touching or hugging someone who has HIV/AIDS.
  • Public bathrooms or swimming pools.
  • Sharing cups, utensils, or telephones with someone who has HIV/AIDS.
  • Bug bites.
  • Donating blood.

Who can get HIV?

Anyone can get HIV if they are exposed to the virus. You have a higher risk of getting HIV if you:

  • Have sex with many partners (men or women).
  • Have unsafe sex with an infected person.
  • Share needles to take drugs or steroids.
  • Have unprotected sex for drugs or money.
  • Have another sexually transmitted infection (STI).

What behaviors are the most risky for getting or transmitting HIV?

Since there is a fairly high number of people who have HIV and don’t know it, you should be tested for HIV so you know your status. Being intoxicated is risky because you are more likely to engage in risky sex if you are drunk or high. In terms of sex acts, anal sex and vaginal intercourse are the most risky behaviors.

Are women more likely to get HIV?

Yes. Biologically speaking, a woman is more vulnerable to heterosexual transmission of the disease because the genitalia are easily exposed to seminal fluids.

Gender inequality has great influence on the spread of HIV/AIDS among women. In some cultures, many women and girls are often put in situations where they engage in non-consensual sex or have sex for money.

In the U.S., minority communities have been hit the hardest by HIV. African American and Hispanic women together represent less than 25% of all U.S. women, yet they account for more than 78% of AIDS cases reported among women in the country.

What are the symptoms of HIV?

Some people get flu-like symptoms a month or two after they have been infected. This is called the acute stage. These symptoms often go away within a week to a month.

You can have HIV for many years before feeling ill. This is called clinical latency or the chronic stage.

AIDS is the most severe stage of HIV infection. In this stage, the immune system has been weakened by the HIV virus and is less able to fight off infections. Opportunistic infections are infections that could generally be fought off by a healthy immune system. In order to be diagnosed with AIDS, you have to have fewer than 200 CD4 cells per cubic millimeter of blood (200 cells/mm3), OR you must have developed what are called opportunistic infections (OIs) or certain cancers. You can develop AIDS even if your CD4 count is not 200 or lower.

What conditions are considered to be opportunistic?

Some of the most common of these OIs/cancers among HIV-positive people include:

Cancer: The types of cancers that are you are more likely to get if you have AIDs include lymphoma, Kaposi’s sarcoma, invasive cervical cancer, anal cancer, liver cancer, and cancers of the mouth, throat and lungs.

Candidiasis (thrush): This condition is caused by Candida fungus. It can happen in the skin, nails and mucous membranes throughout the body, such as the mouth or the vagina. The cases can be troublesome, but thrush is especially dangerous when it affects the esophagus or parts of the respiratory system (trachea, bronchi, lung tissue).

Pneumonia: This respiratory condition is most commonly caused by _Pneumocystis jirovecii and the bacterium Streptococcus pneumoniae._

Salmonella: This infection is spread through contaminated food and water. It causes diarrhea, vomiting and nausea.

Toxoplasmosis: This disease is caused by a parasites that live in cats and rodents and other warm-blooded animals. The infection is spread through the feces. Toxoplasmosis can cause severe problems in the lungs, heart, brain and other organs. If you have a cat, wear gloves to change the litter and be thorough in washing your hands.

Diagnosis and Tests

How can I know if I have HIV?

The only way to know if you have HIV is to take an HIV test. Many medical groups recommend routine voluntary HIV screening of all patients aged 18 to 75 years of age as a normal part of medical care. The reason for this is that nearly one out of seven people infected with HIV are not aware that they have the infection.

How is an HIV test performed?

Before taking an HIV test:

  • Ask the clinic what privacy rules it follows.
  • Ask your healthcare provider any questions you have about HIV, AIDS, or the HIV test.

To do the HIV test, a small sample of blood is taken from your arm. The blood is sent to a lab and tested for HIV.

Home testing is available. The sample can be obtained via oral secretions (saliva), or a blood sample from a finger-stick test strip that is then mailed to a laboratory for screening. Positive results must be confirmed by your doctor before a diagnosis of HIV infection can be established.

Some clinics perform HIV tests without ever taking your name (anonymous testing). You must go back to the clinic to get your results. A positive test means you have HIV. A negative test means no signs of HIV were found in your blood.

If your test comes back positive, your healthcare provider is likely to recommend other tests to assess your health. These may include a complete blood count (CBC), along with:

Management and Treatment

How is HIV/AIDs treated?

If you have HIV, your healthcare provider will prescribe antiretroviral therapy (ART) to reduce HIV in blood (viral load) to an undetectable amount and to slow progression through the stages of HIV.


How can I keep from getting HIV?

The best way to protect yourself is to avoid activities that put you at risk. There's no way to tell by looking at someone if he or she has HIV. Always protect yourself. Use latex condoms (rubbers) whenever you have any type of sex (vaginal, anal or oral).

  • Don't use condoms made from animal products.
  • Use water-based lubricants (lotion).
  • Never share needles to take drugs.
  • Avoid getting drunk or high. Intoxicated people might be less likely to protect themselves.
  • Consider getting tested—it is really important to be aware of your HIV status.

If you are a healthcare worker, you are at a slightly higher risk of getting HIV from a needle-stick injury, skin contact with contaminated fluid or from human bites. You should follow universal precautions:

  • Always wear protective equipment when dealing with blood and body fluids.
  • Follow careful hand-washing guidelines when dealing with such fluids.
  • Follow safe handling guidelines for needles and sharp instruments.
  • Be aware of post-exposure policies at your workplace.

If you are in a relationship with a partner who has HIV, or you are at high risk for any other reason, consider using pre-exposure prophylaxis, commonly called PrEP. This means taking one of two medicines every day, emtricitabine-tenofovir (TDF, Truvada®) or emtricitabine-tenofovir alafen (Descovy®).

If you are a person with HIV who is in a relationship with a person who is HIV-negative, you should also be on a medication regimen.

It's important to use a condom correctly to protect yourself against HIV. Use a male condom for any sex act that involves the penis.

You can also protect the vagina or anus with dental dams or internal condoms. Dental dams are flat pieces of polyurethane or latex that you can put over the vagina or anus if you are having oral sex. An internal condom (also called female condom) can be used by insertion into the vagina or anus. You should only use one type of condom at a time. Do not use both a male condom and internal condom.

If you are pregnant and have HIV, you can take medicine that will reduce the risk of passing the virus to your child.

Outlook / Prognosis

What is the outlook for someone with HIV/AIDS?

If you are diagnosed with HIV and you start ART soon after, your immune system will not be as compromised. If you continue to take your medicines every day, your outlook is very good.

ART can keep blood levels undetectable but cannot entirely rid the body of the virus (which remains inactive in your cells). If you do not keep up on your medication, the virus goes back into the blood.

If you have HIV and don’t treat it, it can take about 10 years to lead to AIDS. If you have AIDS and don’t treat it, the survival rate is about three years.

It is so important to know that people who have HIV and who follow treatment guidelines are able to live full lives for nearly as long as HIV-negative people.

Living With

When should you call the doctor if you have HIV or you think you have been exposed to HIV?

Call your healthcare provider immediately if you think you have been exposed so that you can be tested. It is important to begin treatment as soon as possible if you do have HIV.

There is also post-exposure prophylaxis (PEP), which is used in emergencies and should be started within 72 hours after the possible exposure. This involves taking antiretroviral therapy (ART) after this exposure. ART may be prescribed after sexual assault, or if you think you have been exposed during consensual sex or drug-taking.

If you already know you have HIV, you should follow your healthcare provider’s instructions on when to call. It is important to treat any type of infection, so call if you have new symptoms or things like a fever, sweating episodes, diarrhea, and so on. It’s better to check with your doctor if you have any kind of symptom that worries you.

The main feature of managing AIDS is to continue to take your medicines and to fight back at opportunistic infections at the first sign of them.

Should I get vaccines if I have HIV/AIDS?

Check with your healthcare provider. Certain vaccines are generally recommended, including:

  • Influenza (flu) vaccine.
  • Hepatitis B vaccine.
  • Human papillomavirus (HPV) vaccine if you are age 26 or younger.
  • Meningococcal series of shots.
  • Pneumonia vaccine.
  • Tetanus, diphtheria and pertussis (Tdp) vaccine, with a repeat every 10 years of the tetanus/diphtheria (Td) vaccine.

You should probably avoid live vaccines, such as the ones for chickenpox and measles, mumps and rubella (MMR). This is true especially if your CD4 numbers are 200 or lower. Make sure you discuss vaccine questions with your healthcare provider.

HIV can affect how well the vaccine works. It can also make your viral load increase for a time because your immune system is stimulated by the vaccine.


What resources are available for people with HIV/AIDS?

This list is not a complete one, but it may be helpful if you are looking for resources.

Last reviewed by a Cleveland Clinic medical professional on 04/24/2020.


  • US Department of Health and Human Services. AIDs info. ( Accessed 4/27/2020.
  • Centers for Disease Control & Prevention. HIV Basics. ( Accessed 4/27/2020.
  • ( Accessed 4/27/2020.
  • Planned Parenthood. HIV/AIDS. ( Accessed 4/27/2020.
  • Cleveland Clinic. Center for Continuing Education. HIV for the Primary Care Physician. ( Accessed 4/27/2020.
  • Avert. HIV & Occupational Exposure Fact Sheet. ( Accessed 4/27/2020.

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