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; or (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. 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. The CDC
currently recommend testing six months after the last possible exposure to HIV.
Where Can I Get More Information About HIV and AIDS?
There are many valuable sources of HIV/AIDS information,
including your state or local health department (see your local phonebook), and
your local AIDS service organization (see your local phonebook). You can also
access resources over the internet. For more information, see amfAR's Treatment
Directory resource list.
How Can I Help Fight HIV/AIDS?
Everyone can play a role in dealing with this epidemic. Here
are just a few suggestions for how you can make a difference in the fight
against HIV/AIDS:
Volunteer with your local AIDS service organization.
Talk with the young people you know about HIV/AIDS.
Urge government officials to provide adequate funding for
AIDS research, prevention education, medical care, and support services.
Speak out against AIDS-related discrimination.
Support continued research to develop better treatments and
a safe and effective AIDS vaccine by making a donation to amfAR.
