Picture of an AIDS awareness ribbon

What is AIDS?

AIDS stands for acquired
immunodeficiency syndrome. It is caused by the human immunodeficiency virus (HIV). This
virus kills or impairs cells of the immune system. Over time, it destroys the body’s
ability to fight infections and certain cancers. HIV is most often spread by sexual
contact with an infected partner. 

AIDS refers to the most advanced
stages of an HIV infection. HIV-infected people have AIDS if they have fewer than 200
CD4+ T cells. Healthy adults usually have CD4+ T-cell counts of around 600 or more.
These T4 cells are key fighters in the immune system. HIV-infected people also have AIDS
if they have one or more health conditions (including opportunistic infections and
certain cancers) that affect people with advanced HIV.

The CDC estimates that 1.5 million
adults and adolescents are living with HIV infection in the U.S. The HIV epidemic is
getting under control in most parts of the world. That’s because testing and treatment
have become more available.

How is HIV transmitted?

Sexual contact

HIV is spread most
often by unprotected (without a condom) sexual contact with an infected
person whose own HIV is not under control with treatment. The virus
enters the body through the lining of the vagina, penis, or anus during
sexual activity. Unprotected anal sex carries the highest risk of

Blood contamination

HIV may also be
spread through contact with infected blood. But due to the screening of
blood for HIV in the U.S., the risk of getting HIV from blood
transfusions is very low.


HIV is often spread
by sharing needles, syringes, or drug use equipment with someone who is
infected with the virus and whose virus is not under control with
treatment. Contaminated razors and other sharp devices (such as
fingerstick machines) can also transmit HIV. Transmission from patient to
healthcare worker, or vice-versa, through accidental sticks with
contaminated needles or other medical tools is rare.


HIV also can be
spread to babies born to, or breastfed by, mothers infected with the
virus, if the mother’s HIV is not under control with treatment.

HIV/AIDS cannot be
spread through:

  • Saliva

  • Sweat

  • Tears

  • Casual
    contact, such as sharing food or food utensils, towels, and

  • Swimming

  • Telephones

  • Toilet

  • Biting insects
    (such as mosquitoes)

What are the symptoms of HIV/AIDS?

Many people develop a flu-like
illness within 2 to 6 weeks after exposure to the HIV virus. But about half do not get
any symptoms at all when they first become infected. The symptoms that do appear often
go away within a week to a month. Plus, they may be mistaken for some other illness. The
symptoms may include:

  • Fever

  • Headache

  • Malaise

  • Enlarged lymph nodes

  • Rash

Lasting or severe symptoms may not
start for 10 years or more after HIV first enters the body in adults. They may start
within 2 years in children born with an HIV infection. This “asymptomatic” period of the
infection is highly variable from person to person. But during this time, HIV is
actively infecting and killing cells of the immune system. Its most obvious effect is a
drop in the blood levels of CD4+ T cells. The virus initially disables or destroys these
cells without causing symptoms.

As the immune system breaks down,
complications start. The following are the most common complications, or symptoms, of
HIV/AIDS. But each person may have different symptoms. They may include:

  • Lymph nodes that stay
    enlarged for more than 3 months

  • Lack of energy

  • Weight loss

  • Frequent fevers and

  • Lasting or frequent yeast
    infections (oral or vaginal)

  • Lasting skin rashes or flaky

  • Recurrent diarrhea

  • Short-term memory loss

  • One or more infections
    (opportunistic infections) linked to having a weakened immune system. These
    include tuberculosis and certain types of pneumonia.

Some people have frequent and
severe herpes infections. These may cause mouth, genital, or anal sores, or a painful
nerve disease known as shingles. Children may have problems developing or fail to

During an HIV infection, most
people have a gradual drop in the number of CD4+ T cells. Though some people may have
abrupt and dramatic drops in their counts.

The symptoms of an HIV infection
may look like other health problems. Always talk with your healthcare provider for a
diagnosis. Rapid diagnostic tests are available and early diagnosis is important. 

How is HIV/AIDS diagnosed?

Early HIV infection often causes no
symptoms. It must be detected by testing a person’s blood for
antibodies—disease-fighting proteins—against HIV or by testing for the actual virus.
Testing may not be positive until 2 to 12 weeks after infection. People exposed to HIV
should be tested for the virus as soon as they think they may have been exposed to

If a person has been recently
exposed or potentially exposed to HIV and initial testing is negative, repeat testing in
2 to 12 weeks will often be needed.

Treatment for HIV/AIDS

As with many other conditions,
early detection offers better treatment. Antiviral medicines for HIV can stop the virus
from further damaging the body. They can allow some or all of the damage to be healed.
People who take these medicines can often live a normal life span and have a normal sex
and family life.

There is currently no cure for
HIV. But a person who takes antiviral medicines may be able to keep the virus completely
under control. This is called “undetectable.” Talk with your healthcare provider for
more information about the excellent medicines available for treating HIV/AIDS.

Are we getting close to finding a vaccine
for AIDS?

Billions of dollars are being spent
each year to find a vaccine that might either prevent HIV infection or help the body to
control the infection better. As of now, no vaccine has yet been shown to be effective
enough to be used.