Human immunodeficiency virus (HIV) is a virus that attacks a part of the immune system. It targets white blood cells called CD4 (T cells). They are needed to fight off infections and other diseases. Low levels of CD4 cells make it harder for the body to stop or control infections and diseases.

AIDS is a late stage of HIV infection. It is a sign of severe damage to the immune system. This level of damage can allow infections that do not usually occur in healthy people. It also allows the growth of some cancers.

Immune System

Immune system white blood cell
HIV destroys white blood cells vital to the immune system.
Copyright © Nucleus Medical Media, Inc.


HIV is spread through contact with HIV-infected body fluids. This includes blood, semen, vaginal fluid, and breast milk.

HIV is most commonly spread through:

  • Sexual contact with an HIV-infected person, especially vaginal or anal sex
  • Transfer of HIV from a mother to child during pregnancy, childbirth, or breastfeeding
  • HIV-contaminated needle

Rarely, HIV can be spread through:

  • A blood transfusion with HIV-infected blood
  • Blood from an HIV-infected person getting into an open wound of another person
  • Being bitten by someone infected with HIV
  • Sharing personal hygiene items with an HIV-infected person

Risk Factors

Factors that may increase your chance of HIV infection include:

  • Sex with a high-risk individual or individual already infected with HIV
  • Multiple sexual partners
  • Sex without using a condom including vaginal and anal sex
  • Having other sexually transmitted diseases
  • Injecting drugs with used or dirty needles
  • Regular exposure to HIV-contaminated blood or other body fluids
  • Being born to an HIV-infected mother
  • Receiving donor blood products, tissue, organs, or artificial insemination before 1985 (infections from donated tissue after 1985 is unlikely due to strict screening processes)
  • Uncircumcised penis—circumcised men are less likely to develop HIV infection than uncircumcised men


HIV may not cause problems for a number of years.

Early symptoms may appear 1 to 2 months after an infection. They may last a couple of weeks. Early symptoms may include:

  • Fever
  • Joint and muscle aches
  • Night sweats
  • Fatigue
  • Swollen lymph nodes in armpits, neck, or groin
  • Headache
  • Sore throat
  • Rash
  • Diarrhea

There may be no additional symptoms for months to years. Symptoms that do occur over the years may include:

  • Lack of appetite
  • Fatigue
  • Muscle wasting
  • Swollen lymph glands all over the body
  • Memory loss
  • Development of lots of warts
  • Fungal infections of the mouth, fingernails, toes
  • Repeated vaginal infections
  • Flare-ups of prior conditions, such as eczema, psoriasis, or herpes
  • Chronic diarrhea

If left untreated, HIV infection may progress to AIDS. This may happen when the number of CD4 cells fall below certain levels. Infections that are rare in healthy people, begin to arise. Examples include:


Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests to confirm a diagnosis of HIV infection include:

  • HIV antibody test—to detect specific proteins in blood or saliva
  • Plasma RNA, or viral load test—to detect the amount of HIV in the blood
  • Your doctor may also test for other infections. You may be tested for one or more of the following:
    • Tuberculosis
    • Hepatitis
    • Sexually transmitted diseases (STDs)


There is no cure for HIV at this time. The goal of treatment is to control HIV. Treatment, called antiretroviral treatment, can:

  • Prevent progression to AIDS
  • Decrease the risk of passing the virus to someone else
  • Play an important role in treatment for some HIV related infections and cancers

Antiviral medicine can stop the virus from spreading in the body. However, it cannot get rid of the virus. Once treatment is stopped the virus will grow and spread again.

Antiviral medicines are often given in combination. Categories of these medicines include:

  • Nucleoside reverse transcriptase inhibitors
  • Nonnucleoside reverse transcriptase inhibitors
  • Protease inhibitors
  • HIV-1 integrase inhibitors
  • HIV-1 fusion inhibitors
  • CC chemokine receptor 5 antagonists

AIDS increases the risk of infections and cancer. Medicine may help to fight these infections. These may include antibiotics or antifungal medicine.

The doctor may recommend some steps to prevent new infections. This will depend on your needs and current risk factors. Options may include:

  • Vaccination
  • Prophylaxis medicine—will be given before an infection develops if you are at high risk

Regular check-ups will help you stay on track. Blood tests will show if the virus has changed and if treatment is working.

Chronic diseases can impact your day to day life. There are many support options that may help with these challenges. Options include:

  • Support group
  • Local organizations
  • Counseling
  • Peer groups

There are steps you can take to decrease the risk of spreading HIV to others:

  • If you have sex, use a latex condom every time. It will be needed during any sexual act with an exchange of body fluids. Other options to consider:
    • A female condom may be used. This type of condom has not been well studied. However, a female condom is better than nothing.
    • A dental dam can be used during oral sex. It is a small square of latex.
  • Follow your care plan. Proper treatment may help to decrease the chance of passing to others.
    • Take any medicine as directed. Tell your doctor if side effects or costs are causing problems.
    • Work with your doctor to monitor your viral load. The infection is less likely to pass with a low viral load.
  • Let past, present, and future sexual partners know about the infection. Encourage them to get tested.
  • Do not donate blood or organs.
  • If you are not planning a pregnancy, ask your doctor about contraception.
  • If you do wish to become pregnant, talk to your doctor. There are ways to lower your baby's risk of being born infected with HIV.
  • If you have a baby, do not breastfeed. HIV can pass through breastmilk.