early HIV infection often causes no symptoms, a doctor or
other health care worker usually can diagnose it by testing
a person's blood for the presence of antibodies (disease-fighting
proteins) to HIV. HIV antibodies generally do not reach levels
in the blood which the doctor can see until one to three months
following infection, and it may take the antibodies as long
as six months to be produced in quantities large enough to
show up in standard blood tests.
exposed to the virus should get an HIV test as soon as they
are likely to develop antibodies to the virus. By getting
tested early, they can get the right treatment at a time when
their immune systems are most able to combat HIV and thus
prevent the emergence of certain opportunistic infections
(see Treatment below). Early testing also alerts HIV-infected
people to avoid high-risk behaviors that could spread the
virus to others.
doctors' offices or health clinics can do HIV testing and
will usually offer counseling to the patient at the same time.
Of course, individuals can be tested anonymously at many sites
if they are concerned about confidentiality.
Doctors diagnose HIV infection by using two different types
of antibody tests, ELISA and Western Blot. If a person is
highly likely to be infected with HIV and yet both tests are
negative, a doctor may look for HIV itself in the blood. The
person also may be told to repeat antibody testing at a later
date, when antibodies to HIV are more likely to have developed.
born to mothers infected with HIV may or may not be infected
with the virus, but all carry their mothers' antibodies to
HIV for several months. If these babies lack symptoms, a definitive
diagnosis of HIV infection using standard antibody tests cannot
be made until after 15 months of age. By then, babies are
unlikely to still carry their mothers' antibodies and will
have produced their own, if they are infected. New technologies
to detect HIV itself are being used to more accurately determine
HIV infection in infants between ages 3 months and 15 months.
A number of blood tests are being evaluated to determine if
they can diagnose HIV infection in babies younger than 3 months.
AIDS first surfaced in the United States, no medicines were
available to combat the underlying immune deficiency and few
treatments existed for the opportunistic diseases that resulted.
Over the past 10 years, however, researchers have developed
drugs to fight both HIV infection and its associated infections
Food and Drug Administration has approved a number of drugs
for treating HIV infection. The first group of drugs used
to treat HIV infection, called nucleoside reverse transcriptase
(RT) inhibitors, interrupts an early stage of the virus making
copies of itself. Included in this class of drugs (called
nucleoside analogs) are AZT (also known as zidovudine or ZDV),
ddC (zalcitabine), ddI (dideoxyinosine), d4T (stavudine),
and 3TC (lamivudine). These drugs may slow the spread of HIV
in the body and delay the onset of opportunistic infections.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs),
such as delvaridine (Rescriptor) and nevirapine (Viramune),
are also available for use in combination with other antiretroviral
recently, a second class of drugs has been approved for treating
HIV infection. These drugs, called protease inhibitors, interrupt
virus replication at a later step in its life cycle. They
include ritonavir (Norvir), saquinivir (Invirase), indinavir
(Crixivan), amprenivir (Agenerase), and nelfinavir (Viracept).
Because HIV can become resistant to both classes of drugs,
combination treatment using both is necessary to effectively
suppress the virus.
available antiretroviral drugs do not cure people of HIV infection
or AIDS, however, and they all have side effects that can
be severe. Some of the nucleoside RT inhibitors may cause
a depletion of red or white blood cells, especially when taken
in the later stages of the disease. Some may also cause an
inflammation of the pancreas and painful nerve damage. Other
complications, including lactic acidosis and severe hepatomegaly
(enlarged liver) with steatosis (fatty liver) that may result
in liver failure and death, have also been reported with the
use of antiretroviral nucleoside analogs alone or in combination,
including AZT, ddI, ddC, 3TC, and abacavir.
The most common side effects associated with protease inhibitors
include nausea, diarrhea, and other gastrointestinal symptoms.
In addition, protease inhibitors can interact with other drugs
resulting in serious side effects.
have credited highly active antiretroviral therapy, or HAART,
as being a major factor in reducing the number of deaths from
AIDS in this country by 47 percent in 1997. HAART is a combination
of several drugs to treat patients. These drugs include reverse
transcriptase inhibitors and protease inhibitors. Patients
who are newly infected with HIV as well as AIDS patients can
take the combination.
is not a cure. The health of HIV and AIDS patients has benefited
dramatically by combining protease inhibitors with other AIDS
drugs, but there are drawbacks. Also, though HIV may not be
found in the patients successfully treated with HAART, researchers
know that it is still present, lurking in hiding places such
as the lymph nodes, the brain, testes, and the retina of the
number of drugs are available to help treat opportunistic
infections to which people with HIV are especially prone.
These drugs include foscarnet and ganciclovir, used to treat
cytomegalovirus eye infections, fluconazole to treat yeast
and other fungal infections, and trimethoprim/sulfamethoxazole
(TMP/SMX) or pentamidine to treat Pneumocystis carinii pneumonia
In addition to antiretroviral therapy, adults with HIV whose
CD4+ T-cell counts drop below 200 are given treatment to prevent
the occurrence of PCP, which is one of the most common and
deadly opportunistic infections associated with HIV. Children
are given PCP preventive therapy when their CD4+ T-cell counts
drop to levels considered below normal for their age group.
Regardless of their CD4+ T-cell counts, HIV-infected children
and adults who have survived an episode of PCP are given drugs
for the rest of their lives to prevent a recurrence of the
individuals who develop Kaposi's sarcoma or other cancers
are treated with radiation, chemotherapy or injections of
alpha interferon, a genetically engineered naturally occurring
no vaccine for HIV is available, the only way to prevent infection
by the virus is to avoid behaviors that put a person at risk
of infection, such as sharing needles and having unprotected
Many people infected with HIV have no symptoms. Therefore,
there is no way of knowing with certainty whether a sexual
partner is infected unless he or she has repeatedly tested
negative for the virus -- and has not engaged in any risky
People should either abstain from having sex or or use latex
condoms, which may offer partial protection, during oral,
anal, or vaginal sex. Only condoms made of latex should be
used, and water-based lubricants should be used with latex
some laboratory evidence shows that spermicides can kill HIV,
researchers have not found that these products can prevent
a person from getting HIV.
risk of HIV transmission from a pregnant woman to her baby
is significantly reduced if she takes AZT during pregnancy,
labor and delivery, and her baby takes it for the first six
weeks of life.
NIAID-supported investigators are conducting an abundance
of research on HIV infection, including the development and
testing of HIV vaccines and new therapies for the disease
and some of its associated conditions. Twenty-eight HIV vaccines
are being tested in people, and many drugs for HIV infection
or AIDS-associated opportunistic infections are either being
developed or being tested. Researchers also are investigating
exactly how HIV damages the immune system. This research is
suggesting new and more effective targets for drugs and vaccines.
NIAID-supported investigators also continue to trace how the
disease progresses in different people.
are investigating and testing chemical barriers, such as topical
microbicides, that people can use in the vagina or in the
rectum during sex to prevent HIV transmission. They also are
looking at other ways to prevent transmission such as controlling
sexually transmitted diseases and modifying people's behavior
as well as ways to prevent transmission from mother to child.
a component of the National Institutes of Health, supports
research on AIDS, tuberculosis and other infectious diseases
as well as allergies and immunology.
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892
U.S. Department of Health and Human Services