The term AIDS (Acquired Immune Deficiency Syndrome) refers to the
most advanced stages of an infection caused by the human immunodeficiency virus
(HIV). The current definition of AIDS includes:
- All HIV-infected people who have fewer than 200 CD4+ T cells
(also called T4 cells). These cells are key infection fighters in the body’s
immune system. Healthy adults usually have CD4+ T-cell counts of around 600 or
- HIV-infected people who have been diagnosed with 1 or more
health conditions that affect people with advanced HIV disease. These conditions
include certain cancers. They also include certain infections that occur because
of HIV’s effect on the immune system (called opportunistic infections).
According to the CDC, about 1.5 million adults and teens are
living with HIV infection in the U.S. Many more people are living with HIV infection
outside the U.S., particularly in sub-Saharan Africa. The HIV epidemic is still not
well-controlled in some parts of the world. But this is improving steadily as
effective medicines have become more widely available.
AIDS is caused by the human immunodeficiency virus (HIV). HIV
destroys or hurts immune system cells. It weakens the body’s ability to fight
infections and certain cancers. HIV is most often spread by having sex with an
infected partner whose HIV is not diagnosed or not under control. Another way to
spread HIV is by having contact with infected blood from contaminated needles,
syringes, or other drug equipment.
HIV can’t be cured. But it can be controlled. And much of the
damage from the infection can be reversed or prevented. But if HIV is left
untreated, serious infections and cancers occur because of the weakened immune
system. And the virus can be passed on to others.
The risk of becoming infected with HIV depends on the type of
activity. HIV is spread through blood, pre-seminal fluid and semen, fluids from the
vagina and rectum, and breastmilk. So these types of behaviors put people at risk
getting or becoming infected with HIV:
- Having vaginal or anal sex with a person infected with HIV
whose virus is not under control. Sexual contact is the most common way the
virus is spread. The virus enters the body through the lining of the vagina,
penis, rectum, or mouth during sexual activity. Unprotected anal sex has the
highest risk of transmission.
- Having multiple sex partners. This includes any partners
whose HIV status is not known. It also includes a partner who has HIV, but whose
virus is not under control or is uncertain of the control of their HIV.
- Having high-risk sexual partners. This includes a partner
who has a sexually transmitted infection (STI), is a sex worker, or has sex
with many other people. Someone who injects or sniffs drugs is also a high-risk
- Sharing needles, syringes, or other drug equipment with
someone with HIV whose virus is not under control or someone with uncertain HIV
Other factors includes:
Using alcohol and other
These can harm someone’s judgment. They make it more likely that
people will do risky things such as having unprotected sex.
Having a sexually transmitted
). STIs can cause changes in the tissue of the vagina or
penis. They can make it easier for HIV to pass while you’re having sex. And a
person with one STI is more likely to pick up another, including HIV.
Having an accidental stick
from a needle or medical device contaminated with HIV
. But it is rare
for a person with HIV to spread the virus to a healthcare worker this way. Or
for a healthcare worker to spread the virus to a patient.
Having a blood
HIV may also be spread through contact with infected blood.
But the risk of getting HIV from blood transfusions is very low. This is because
blood is screened for signs of HIV infection in the U.S.
Having sex without knowing
your partner’s HIV status.
Risks to an unborn child. A
mother infected with HIV can give her baby the virus before or during birth. This
especially true if her HIV is not well controlled. She can also pass the virus by
breastfeeding. Pregnant women should always be tested and treated for HIV.
Being exposed to these things does
not put you at risk for
- Casual contact, such as sharing food utensils, towels, and
- Swimming pools
- Toilet seats
- Biting insects (such as mosquitos)
Many people develop a flu-like illness within 2 to 6 weeks after
exposure to the HIV virus. But about 5 out of 10 people don’t have any symptoms at
all when they first become infected. In addition, the symptoms that do appear often
go away within a week to a month. And they are often mistaken for those of another
viral infection. These symptoms may include:
- General feeling of discomfort (malaise)
- Enlarged lymph nodes
- Sore throat
Constant or severe symptoms may not show up for 10 years or more
after HIV first enters the body in adults. In children born with an HIV infection,
it may take 2 years for symptoms to appear. This period of no symptoms can be
different for each person. But during this time, HIV is actively infecting and
killing immune system cells and other cells throughout the body. Its most clear
effect is a decrease in the number of CD4+ T cells. These cells are key infection
fighters in the immune system.
As the immune system weakens, complications or symptoms begin to
appear. Symptoms of advanced HIV disease and AIDS may be different for each person.
Symptoms may include:
- Lymph nodes that stay enlarged for more than 3 months
- Lack of energy
- Weight loss
- Frequent fevers and sweats
- Constant or frequent yeast infections (oral or vaginal)
- Constant skin rashes or flaky skin
- Diarrhea that keeps coming back
- Short-term memory loss
- 1 or more infections (opportunistic infections) linked to
having a weakened immune system. These include tuberculosis and certain types of
Some people develop frequent and severe herpes infections. These
cause mouth, genital, or anal sores, or a painful nerve disease known as shingles.
Children may have delayed development or slowed growth (failure to thrive).
During the course of the HIV infection, most people have a slow
decline in the number of CD4+ T cells. Some people may have sudden and severe drops
in these cell counts.
The symptoms of HIV infection may look like other health
conditions. Always talk with your healthcare provider for a diagnosis. Quick
diagnostic tests are available and early diagnosis is important.
Several types of HIV tests are used to diagnose HIV infection.
Early HIV infection often causes no symptoms. It must be found by testing a person’s
blood for proteins (antibodies) made against HIV. Or the virus itself can be
detected. Tests used to find antigen-antibody are a preferred method of testing. In
this case, antigens are a portion of the virus. They are a sign of the active virus
and also cause a response from the body’s immune system. Antibodies are made by the
body in an attempt to fight the virus and its antigens. Testing for antibodies and
the virus is generally positive within 10 to 28 days after infection. But it may
sometimes take longer, especially if an older HIV test (not the antigen-antibody
test) is used. People exposed to HIV should be tested for HIV infection as soon as
possible. In some cases a person may have been very recently exposed or possibly
exposed to HIV and that very early testing is negative. This is much less likely now
with newer antigen-antibody testing. You may need to do repeat testing in 1 to 4
As with many other conditions, finding HIV early offers more
chances for successful treatment. Antiviral (or antiretroviral) medicines for HIV
can stop the virus from further harming the body. This allows some or all of the
damage to be healed. Antiretroviral treatment that fully controls the virus can also
work well to prevent spreading the virus to others. People can then often live a
normal life span and have a normal sex life and family life.
There is currently no cure for HIV infection. But people who take
the medicines and stay on them may be able to keep the virus completely under
control. Almost everyone with HIV infection will benefit from and needs anti-HIV
(antiretroviral) treatment. Everyone whose HIV infection has progressed to AIDS
needs antiretroviral treatment. Untreated AIDS will always lead to death. There is
no other effective treatment other than antiretrovirals. Talk with your healthcare
provider for more information about various medicines for treating HIV/AIDS.
A lot of research is being done to find a vaccine that might
either prevent HIV infection or help the body to better control HIV infection.
Currently, no vaccine has been shown to work well enough to be used.
- AIDS is caused by the human immunodeficiency virus (HIV).
HIV destroys or hurts immune system cells. It weakens the body’s ability to
fight infections and certain cancers.
- HIV is most often spread by having sex with an infected
partner. It can also spread by having contact with infected blood from
contaminated needles, syringes, or other drug equipment.
- A mother infected with HIV can give her baby the virus
before or during birth. She can also pass the virus by breastfeeding.
- Many people have a flu-like illness within 2 to 6 weeks
after exposure to the HIV virus. But about 5 out of 10 people don’t have any
symptoms at all at first.
- HIV can’t be cured. But it can be well controlled with
Tips to help you get the most from a visit to your healthcare
- Know the reason for your visit and what you want to
- Before your visit, write down questions you want
- Bring someone with you to help you ask questions and
remember what your provider tells you.
- At the visit, write down the name of a new diagnosis, and
any new medicines, treatments, or tests. Also write down any new instructions
your provider gives you.
- Know why a new medicine or treatment is prescribed, and how
it will help you. Also know what the side effects are.
- Ask if your condition can be treated in other ways.
- Know why a test or procedure is recommended and what the
results could mean.
- Know what to expect if you do not take the medicine or have
the test or procedure.
- If you have a follow-up appointment, write down the date,
time, and purpose for that visit.
- Know how you can contact your provider if you have