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various pills and tabletsAIDS—Treatment (General Information)

There is still no cure for AIDS. There are drugs available that can slow down the damage to a person's immune system and slow down the multiplication of the virus. But there are no drugs yet that eliminate HIV completely from a person's body.

Some scientists think that the new, strong, anti-HIV drugs that are currently available might eliminate all the HIV from a person's body if the drugs were taken for several years, but there are no known cases in which this has happened yet.

There are some drugs available that a person can take to prevent some of the opportunistic infections that people with AIDS are susceptible to. There is little that a person can do to prevent some of the other infections.

AIDS—Treatment (Drug Therapies—General Information)

The best and most widely used treatment for AIDS today is designed to slow down a person's progression from being HIV-positive to having AIDS. This treatment involves taking a "cocktail," or mixture, of several drugs that suppress the multiplication of the human immunodeficiency virus (HIV), which slows down the damage to a person's immune system.

Graph showing number of AIDS deaths since 1987
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The use of these drugs has led to a 44 percent decline in AIDS deaths in the United States, as well as to a significant drop in the number of cases of opportunistic infections among AIDS patients. These drugs do not, however, cure AIDS, because they do not completely eliminate HIV from a person's body.

Following this treatment plan correctly is a challenge for patients. The cost of these drugs is about $10,000 to $15,000 per year per patient. Side effects include nausea, diarrhea, rashes, headaches, and elevated triglyceride and cholesterol levels in the blood. Patients must take a minimum of eight pills every day, some of which must be taken on an empty stomach, some with food, and some with or without other pills. If patients miss doses, they risk not completely suppressing the multiplication of the virus and also risk the appearance of strains of HIV that are resistant to the drugs.

AIDS—Treatment (Drug Therapies—Viral Resistance)

When drugs against HIV do not work, it is often because the virus has become resistant to one of the drugs being used. This resistance is the result of mutations that occur in the viral genes.

Unfortunately, use of anti-HIV drugs can actually promote the reproduction of resistant virus particles. Untreated, HIV makes approximately 10 billion new virus particles every day in an infected person. But HIV does not copy its genetic material very accurately. Because of its sloppy replication, each one of these new virus particles may be different from the parent virus in one or more genes. And because so many virus particles are produced each day, it is very likely that at least one virus is produced each day that is resistant or partially resistant to one of the antiviral drugs the person is taking. This virus particle now has an advantage over other virus particles that are not resistant to the drug, and may reproduce faster than nonresistant strains. Thus, taking anti-HIV drugs can actually promote the reproduction and accumulation of viruses that are not inhibited by the drugs the patient is taking.

Because resistance can occur so easily and because no single drug on the market can inhibit HIV reproduction completely on its own, physicians now treat patients with mixtures (cocktails) of drugs. Physicians must also stay on the lookout for signs of viral resistance emerging in a patient, and if resistance appears to be emerging, must consider new combinations of drugs that will be effective for that patient.

Diagram showing the time course of HIV infection
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HIV—Course of Infection

Many people do not know when they are first infected by HIV because they have no symptoms. Other people don't know because although they get a fever, a headache, and sore muscles and joints for one or two weeks, they think that it is just the flu.

The virus multiplies inside the victim's body for a few weeks (or even a few months) before his or her immune system responds. During this period of time, the person is infected with HIV and can infect others, but he or she won't test positive for HIV.

When a person's immune system begins to respond to the virus by making antibodies, the person will test positive for HIV.

Some people with HIV stay healthy for many years after infection. During this time, however, the virus is damaging the person's immune system. Health care professionals can measure this damage by counting the number of CD4 T-cells a person has. These cells, also called T-helper cells, are part of a person's immune system. Healthy people have between 500 and 1,500 CD4 T-cells in each cubic millimeter of blood, but people with HIV disease have many fewer. As a person's CD4 T-cell count goes down, he or she may start having signs of HIV disease (for example, fevers, night sweats, diarrhea, weight loss, or swollen lymph nodes).

HIV disease is diagnosed as AIDS when the person's CD4 T-cell count drops below 200 CD4 T-cells per cubic millimeter of blood or when the person gets one of the opportunistic infections identified by the Centers for Disease Control and Prevention as characteristic of AIDS.

AIDS progresses at different rates in different people. Some people die within five years of being infected with HIV, whereas other people live for many years, even after they develop AIDS. With treatment, the average time to death after being diagnosed is ten years in the United States; without treatment, the average time to death is two years.

HIV—Definition

HIV stands for "human immunodeficiency virus." HIV is the virus that causes AIDS.

HIV—Definition of HIV-Positive (or HIV Disease)

When a person is infected with HIV, his or her body responds by making antibodies against the virus. (Antibodies are special proteins that fight disease.) Blood tests for AIDS look for antibodies in the blood against HIV. People who have antibodies against HIV in their blood are said to be "HIV-positive." They also might be said to have "HIV disease."

Being HIV-positive (or having HIV disease) is not the same as having AIDS. Many people are HIV-positive, meaning that they have been infected with HIV, but they are not yet sick. As HIV remains in the body, it slowly wears down the immune system.

HIV—Rate of Mutational Change

Untreated, HIV reproduces very rapidly inside a person's body, making approximately 10 billion new virus particles every day. But HIV does not copy its genetic material very accurately. In fact, because of its sloppy replication, each one of these new virus particles may be different from the parent virus in one or more genes. Thus, HIV shows a very rapid rate of mutational change.

The result of this high rate of mutational change is that there exist many different HIV strains, not only in the world, but even within one person's body. This presents a problem for developers of new drugs to combat HIV (some of these different strains may be resistant to the drug) and for developers of vaccines against HIV (the vaccine may be effective against one strain of HIV but not against another).

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