What Is HIV?HIV is
the human immunodeficiency virus that causes AIDS. A member of a group
of viruses called retroviruses, HIV infects human cells and uses the
energy and nutrients provided by those cells to grow and reproduce.
What Is AIDS?AIDS
(acquired immunodeficiency syndrome) is a disease in which the body's
immune system breaks down and is unable to fight off certain infections,
known as "opportunistic infections," and other illnesses that take
advantage of a weakened immune system.
When a person is infected with
HIV, the virus enters the body and lives and multiplies primarily in
the white blood cells. These are the immune cells that normally protect
us from disease. The hallmark of HIV infection is the progressive loss
of a specific type of immune cell called T-helper or CD4 cells.
As
the virus grows, it damages or kills these and other cells, weakening
the immune system and leaving the individual vulnerable to various
opportunistic infections and other illnesses, ranging from pneumonia to
cancer. The U.S. Centers for Disease Control and Prevention (CDC)
defines someone as having a clinical diagnosis of AIDS if they have
tested positive for HIV and meet one or both of these conditions:
They have experienced one or more AIDS-related infections or illnesses.
The number of CD4 cells has reached or fallen below 200 per cubic millimeter of blood (a measurement known as T-cell count).
In healthy individuals, the CD4 count normally ranges from 450 to 1200.How Quickly Do People Infected with HIV Develop AIDS?
In
some people, the T-cell decline and opportunistic infections that
signal AIDS develop soon after initial infection with HIV. Most people
remain asymptomatic for 10 to 12 years, and a few for much longer. As
with most diseases, early medical care can help prolong a person's life.
How Many People Are Affected By HIV/AIDS?The
Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates that
there are now over 34 million people living with HIV or AIDS worldwide.
Most of them do not know they carry HIV and may be spreading the virus
to others. Here in the U.S., nearly one million people have HIV
infection or AIDS roughly one out of every 250 people. At least 40,000
Americans become newly infected with HIV each year, and it is estimated
that half of all people with HIV in the U.S. have not been tested and do
not know they are carrying the virus.
Since the beginning of the
epidemic, AIDS has killed nearly 19 million people worldwide, including
some 425,000 Americans. AIDS has replaced malaria and tuberculosis as
the world's deadliest infectious disease among adults and is the fourth
leading cause of death worldwide. Over 13 million children have been
orphaned by the epidemic.
How Is HIV Transmitted?A
person who is HIV-infected carries the virus in certain body fluids,
including blood, semen, vaginal secretions, and breast milk. The virus
can be transmitted only if such HIV-infected fluids enter the
bloodstream of another person. This kind of direct entry can occur
(1) through the linings of the vagina, rectum, mouth, and the opening at the tip of the penis;
(2) through intravenous injection with a syringe;
(3) through a break in the skin, such as a cut or sore. Usually, HIV is transmitted through:
Unprotected sexual intercourse (either vaginal or anal) with someone who is HIV-infected.
Women
are at greater risk of HIV infection through vaginal sex than men,
although the virus can also be transmitted from women to men. Anal sex
(whether male-male or male-female) poses a high risk mainly to the
receptive partner, because the lining of the anus and rectum are
extremely thin and filled with small blood vessels that can be easily
injured during intercourse.
Unprotected oral sex with someone who is HIV-infected.
There
are far fewer cases of HIV transmission attributed to oral sex than to
either vaginal or anal intercourse, but oral-genital contact poses a
clear risk of HIV-infection, particularly when ejaculation occurs in the
mouth. This risk is increased when either partner has cuts or sores,
such as those caused by sexually transmitted diseases (STDs), recent
tooth-brushing, or canker sores, which can allow the virus to enter the
bloodstream.
Sharing needles or syringes with someone who is HIV-infected.
Laboratory
studies show that infectious HIV can survive in used needles for a
month or more, and should never reuse or share syringes, water, or drug
preparation equipment. This includes needles or syringes used to inject
illegal drugs such as heroin, as well as steroids. Other types of
needles, such as those used for body piercing and tattoos, can also
carry HIV.
Infection during pregnancy, childbirth, or breast-feeding (mother-to-infant transmission).Any
woman who is pregnant or considering becoming pregnant and thinks she
may have been exposed to HIV even if the exposure occurred years ago
should seek testing and counseling. Mother-to-infant transmission has
been reduced to just a few cases each year in the U.S., where pregnant
women are tested for HIV, and those who test positive are provided with
drugs to prevent transmission and counseled not to breast-feed.
How Is HIV Not Transmitted?HIV
is not an easy virus to pass from one person to another. It is not
transmitted through food or air (for instance, by coughing or sneezing).
There has never been a case where a person was infected by a household
member, relative, co-worker, or friend through casual or everyday
contact such as sharing eating utensils and bathroom facilities or
hugging and kissing. (Most scientists agree that while HIV transmission
through deep or prolonged "French" kissing may be possible, it would be
extremely unlikely.)
Here in the U.S., screening the blood supply for
HIV has virtually eliminated the risk of infection through blood
transfusions. (And you cannot get HIV from giving blood at a blood bank
or other established blood collection center.) Sweat, tears, vomit,
feces, and urine do contain HIV, but have not been reported to transmit
the disease (apart from two cases involving transmission from feces via
cut skin). Mosquitos, fleas, and other insects do not transmit HIV.
How Can I Reduce My Risk of Becoming Infected with HIV Through Sexual Contact?If
you are sexually active, protect yourself from HIV infection by
practicing safer sex. Whenever you have sex, use a condom or "dental
dam" (a square of latex recommended for use during oral-genital and
oral-anal sex). When used properly and consistently, condoms are
extremely effective. But remember:
Use only latex condoms (or dental dams). Lambskin products provide little protection against HIV. Use
only water-based lubricants. Latex condoms are virtually useless when
combined with oil- or petroleum-based lubricants such as Vaseline or
hand lotion. (People with latex allergies can use polyethylene condoms
with oil-based lubricants.)
Use protection each and every time you have sex.
If needed, consult a nurse, doctor, or health educator for guidance on the proper use of latex barriers. How Can I Avoid Acquiring HIV From a Contaminated Needle?If
you are injecting drugs of any type, including steroids, do not share
syringes or other injection equipment with anyone else. (Disinfecting
previously used needles and syringes with bleach can reduce the risk of
HIV transmission.) If you are planning to have any part of your body
pierced or to get a tattoo, be sure to see a qualified professional who
uses sterile equipment. Detailed HIV prevention information for drug
users who continue to inject is available from the CDC's National
Prevention Information Network at 1-800-458-5231 or online.
Is There a Link Between HIV and Other STDs?Having
a sexually transmitted disease can increase your risk of acquiring and
transmitting HIV. This is true whether you have open sores or breaks in
the skin (as with syphilis, herpes, chancroid) or not (as with chlamydia
and gonorrhea). Where there are breaks in the skin, HIV can enter and
exit the body more easily. Even when there are no breaks in the skin,
STDs can cause biological changes that may make HIV transmission more
likely. Studies show that HIV-infected individuals who are infected with
another STD are three to five times more likely to contract or transmit
the virus through sexual contact.
Are There Other Ways to Avoid Getting HIV Through Sex?The
male condom is the only widely available barrier against sexual
transmission of HIV. Female condoms are fairly unpopular in the U.S. and
still relatively expensive, but they are gaining acceptance in some
developing countries. Efforts are also underway to develop topical
creams or gels called "microbicides," which can be applied prior to
sexual intercourse to kill HIV and block other STDs that facilitate HIV
infection.
Are Some People at Greater Risk of HIV Infection Than Others?HIV
does not discriminate. It is not who you are, but what you do that
determines whether you can become infected with HIV. Worldwide, sexual
intercourse is by far the most common mode of HIV transmission, but in
the U.S., as many as half of all new HIV infections are now associated
either directly or indirectly with injection drug use (i.e., using
HIV-contaminated needles to inject drugs or having sexual contact with
an HIV-infected drug user). Overall, HIV infection is spreading fastest
in this country among young people, women, African Americans, and
Hispanics.
Are Women Especially Vulnerable to HIV?In
western countries, women are four times more likely to contract HIV
through vaginal sex with infected males than vice versa. This biological
vulnerability is worsened by social and cultural factors that often
undermine women's ability to avoid sex with partners who are
HIV-infected or to insist on condom use. In the U.S., the proportion of
AIDS cases among women more than tripled from 7% in 1985 to 23% in 1999.
African American and Hispanic women, who represent less than
one-quarter of U.S. women, represent nearly 80% of AIDS cases reported
among American women to date.
Are Young People at Significant Risk of HIV Infection?Nearly
half of the roughly 40,000 Americans newly infected with HIV each year
are under the age of 25. Approximately two young Americans become
infected with HIV every hour of every day, and about 25% of the people
now living with HIV in this country became infected when they were
teenagers. Statistics show that by the age of 19, at least half of
females and 60% of males in this country have engaged in sexual
intercourse, and one in six sexually experienced teens has contracted
one or more STDs. Many young people also use drugs and alcohol, which
can increase the likelihood that they will engage in high-risk sexual
behavior.
Are There Treatments for HIV/AIDS?For
many years, there were no effective treatments for AIDS. Today, people
in the United States and other developed countries can use a number of
drugs to treat HIV infection and AIDS. Some of these are designed to
treat the opportunistic infections and illnesses that affect people with
HIV/AIDS. In addition, several types of drugs seek to prevent HIV from
reproducing and destroying the body's immune system:
Reverse
transcriptase inhibitors attack an HIV enzyme called reverse
transcriptase. They include abacavir, delavirdine, didanosine (ddI),
efavirenz, lamivudine (3TC), nevirapine, stavudine (d4T), zalcitabine
(ddC), and zidovudine (AZT). Protease inhibitors attack the HIV enzyme protease and include amprenavir, indinavir, nelfinavir, ritonavir, and saquinavir.Many
HIV patients are taking several of these drugs in combination a regimen
known as highly active antiretroviral therapy (HAART). When successful,
combination or "cocktail" therapy can reduce the level of HIV in the
bloodstream to very low, even undetectable, levels and sometimes enable
the body's CD4 immune cells to rebound to normal levels.
Researchers
are working to develop new drugs known as fusion inhibitors and entry
inhibitors that can prevent HIV from attaching to and infecting human
immune cells. Efforts are also underway to identify new targets for
anti-HIV medications and to discover ways of restoring the ability of
damaged immune systems to defend against HIV and the many illnesses that
affect HIV-infected individuals. Ultimately, advances in rebuilding the
immune system in HIV patients will benefit people with a number of
serious illnesses, including cancer, Alzheimer's disease, multiple
sclerosis, and immune deficiencies associated with aging and premature
birth.
Is There a Cure for AIDS?There
is still no cure for AIDS. And while new drugs are helping many people
with HIV/AIDS live longer, healthier lives, there are many problems
associated with them:
Existing treatments do not work for many people with HIV/AIDS.Anti-HIV
drugs are highly toxic and can cause serious side effects, including
heart damage, kidney failure, and osteoporosis. Many (perhaps even most)
patients cannot tolerate long-term treatment with HAART.
HIV mutates
constantly. In as many as 40% of people on HAART, HIV mutates into new
viral strains that have become highly resistant to current drugs, and as
many as 10% of newly infected Americans are acquiring drug-resistant
strains of the virus.
Because treatment regimens are unpleasant and
complex, many patients occasionally miss doses of their medication.
Failure to take anti-HIV drugs on schedule and in the prescribed dosage
can encourage the development of new viral strains that are resistant to
current HIV drugs.
Even among those who do respond well to
treatment, HAART does not eradicate HIV. The virus continues to
replicate at low levels and often remains hidden in "reservoirs" in the
body, such as the lymph nodes and brain.
Importantly, roughly 95% of
all people with HIV/AIDS live in the developing world, where there is
virtually no access to antiretroviral treatments. Here in the U.S.,
HAART contributed to a significant decline in the annual number of
AIDS-related deaths between 1996 and 1998. But the rate of this decline
has now slowed markedly, and some communities are reporting an increase
in AIDS deaths.
Is There a Vaccine to Prevent HIV Infection?Despite
continued intensive research, experts believe it will be at least a
decade before we have a safe, effective, and affordable AIDS vaccine.
And even after a vaccine is developed, it will take many years before
the millions of people at risk of HIV infection worldwide can be
immunized. Until then, other HIV prevention methods, such as using
condoms and avoiding needle-sharing, will remain essential.
Can You Tell Whether Someone Else Has HIV or AIDS?You
cannot tell by looking at someone whether he or she is infected with
HIV or has AIDS. An infected person can appear completely healthy. But
anyone infected with HIV can infect other people, even if no symptoms
are present.
How Can I Know Whether I'm HIV-Infected?Immediately
after infection, some people may develop mild, temporary flu-like
symptoms or persistent swollen glands. Even if you look and feel
healthy, you may be infected. The only way to know your HIV status for
sure is to be tested for HIV antibodies proteins the body produces in an
effort to fight off infection. This usually requires a blood sample. If
a person's blood has HIV antibodies, that means the person is infected.
Should I Get Tested?If you think you might have been exposed to HIV, you should get tested as soon as possible. Here's why:
Even
in the early stages of infection, you can take concrete steps to
protect your long-term health. Many physicians still recommend a "hit
early and hit hard" approach to anti-HIV therapy.
But even if you
don't begin taking medications right away, regular check-ups with a
doctor who has experience with HIV/AIDS will enable you (and your family
members or loved ones) to make the best decisions about how and when to
begin treatment, without waiting until you get sick.
Taking an active approach to managing HIV may give you many more years of healthy life than you would otherwise have.
If you are HIV-positive, you will be able to take the precautions necessary to protect others from becoming infected.
If
you are HIV-positive and pregnant, you can take medications and other
precautions to significantly reduce the risk of infecting your infant,
including refraining from breast-feeding.
How Can I Get Tested?Most
people are tested by private physicians, at local health department
facilities, or in hospitals. In addition, many states offer anonymous
HIV testing. It is important to seek testing at a place that also
provides counseling about HIV and AIDS. Counselors can answer questions
about high-risk behavior and suggest ways you can protect yourself and
others in the future. They can also help you understand the meaning of
the test results and refer you to local AIDS-related resources.
Though
less readily available, there is also a viral load test that can reveal
the presence of HIV in the blood within 3 to 5 days of initial
exposure, as well as highly accurate saliva tests that are nearly
equivalent to blood tests in determining HIV antibody status. You can
also purchase a kit that allows you to collect your own blood sample,
send it to a lab for testing, and receive the results anonymously. Only
the "Home Access" brand kit is approved by the Food and Drug
Administration. It can be found at most drug stores.
Keep in mind
that while most blood tests are able to detect HIV infection within
four weeks of initial exposure, it can sometimes take as long as three
to six months for antibodies to reach detectable levels.
An eyelash lives about 5 months.
