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HAART is the acronym for highly active antiretroviral therapy, an approach that has revolutionized HIV/AIDS treatment and significantly improved the prognosis for people living with HIV infection. First introduced in 1996, HAART involves daily treatment with three or more antiviral medications to suppress HIV activity and preserve the immune system.
HIV AND THE IMMUNE SYSTEM
Knowing how HIV treatment works helps you understand the importance of taking your medications as prescribed. The goal of HIV treatment is to substantially reduce or stop the virus from reproducing, thereby slowing its destructive effects in the body. HIV attacks your immune system, which is made up of millions of cells that fight infections and other diseases. One of the most important of the infection-fighting cells is the CD4 cell, also known as a T cell. HIV infects CD4 cells and multiplies, or replicates, inside these cells. New viruses are released into the blood and infect other CD4 cells. As CD4 cells are attacked and destroyed by HIV, the immune system becomes progressively weaker and less capable of fighting infections.
HOW HAART WORKS
Anti-HIV drugs, also known as antiretrovirals, work by blocking certain steps in the HIV replication process. When used in combination, antiretroviral drugs reduce the amount of HIV in the blood. The term HIV viral load refers to the number of viruses present in a person's blood. Successful HAART reduces the HIV viral load to low or undetectable levels.
DRUGS USED IN HAART
As of the time of publication, there are more than 30 FDA-approved antiretroviral drugs available to treat HIV infection. The drugs are grouped into classes according to mechanism by which they disrupt the HIV replication process. HIV antiretroviral classes include nucleoside/nucleotide reverse transcriptase inhibitors, or NRTIs; non-nucleoside reverse transcriptase inhibitors, or NNRTIs; protease inhibitors, or PIs; entry/fusion inhibitors; and integrase inhibitors. HAART therapy involves at least three drugs from two different antiretroviral classes. Simultaneously attacking HIV at different points in its replication cycle with multiple drugs keeps HIV levels low, thereby preserving the population of CD4 cells in the body.
DRUG RESISTANCE
HIV replicates at a rapid rate, producing both perfect and imperfect copies of itself. The imperfect copies contain genetic errors, or mutations. Some mutations enable the virus to overcome or sidestep the effects of certain antiretroviral drugs, a phenomenon known as drug resistance. HAART reduces the rate at which HIV develops drug resistance, making long-term viral control possible. There is still a chance, however, that drug resistance may develop while on HAART. If this occurs, the drug combination, or "cocktail," is changed to include only drugs to which the virus remains sensitive.
