HAART, or Highly Active Antiretroviral Therapy, is currently the standard approach to treating HIV infections. Although there is still no cure for HIV, the virus that causes AIDS, HAART is the accepted method for delaying and hopefully stalling the progression of the disease.
HIV, after infecting a person, ravages the body's immune system. Over a period of years after the initial infection, acute phase, and partial recovery, it gradually wears down the immune system's key defensive layer, CD4+ white blood cells, until the body finally loses the capacity to fight off even relatively basic and normally harmless microbes. At that point, the person is said to have AIDS. People with AIDS are not directly killed by HIV: instead, once their immune systems have been effectively destroyed, they fall prey to a range of ailments referred to as opportunistic infections.
It is much more difficult to treat viruses, including HIV, than bacteria (which can be eradicated with antibiotics). However, a range of anti-HIV drugs are now available, known as antiretroviral drugs, which work by targeting various one or more stages in the virus's cycle within the body to prevent it from successfully infecting cells and replicating. Categories of antiretroviral drugs on the market today include integrase inhibitors, nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs), and non-nucleoside reverse transcriptase inhibitors (NNRTIs). The newest classes of drugs are entry inhibitors and integrase inhibitors.
Unfortunately, HIV mutates extremely rapidly, even for a virus. (It is this capacity for rapid mutation which has also stymied researchers searching for a vaccine.) For this reason, when the first anti-HIV medications became available in the 1980s and 1990s, such as AZT (ziduvodine), satisfaction over their often substantial capacity to combat the virus and allow partial immune system recovery was tempered by the knowledge that the virus in a person's system would very quickly (even in mere months) become immune to the drug.
By the mid-1990s, however, enough different anti-HIV medications were becoming available for physicians to try something new: prescribing multiple antiretroviral drugs at once. The theory - confirmed in practice, with remarkably positive results - was that while the virus might quickly develop resistance to one drug in the so-called "cocktail" of medications, it was very unlikely to develop resistance to three or more drugs simultaneously. As a result, any copies of the virus immune to the first drug would still be targeted by the second, and so on. This approach was referred to as Highly Active Antiretroviral Therapy, or HAART.
Today, much more is known about how to actively manage HIV in this manner. Pharmaceutical companies even sell fixed-dose combination drugs, pills containing multiple HIV medications, to simplify the often intimidating pill burden placed on HIV-positive patients, while medical researchers continue to explore which combinations are most effective. In general, a standard combination of drugs under HAART includes two nucleoside-analogue reverse transcriptase inhibitors (NRTIs) and one non-nucleoside-analogue reverse transcriptase inhibitors (NNRTIs), or a protease inhibitor. For instance, doctors might prescribe AZT (zidudovine) and 3TC (lamivudine), both NRTIs, plus Sustiva (efavirenz), an NNRTI.
The advent of HAART is the main reason that HIV has now moved from being terminal to, if not quite chronic, certainly a very-long-term illness. However, it is still not a perfect solution, or a cure. The goal of HAART is to lower viral levels within the body as far as possible, while allowing the immune system to recover as much as possible. Neither goal can be achieved completely, but both can, it now seems, be achieved in large part, for long periods of time.
Still, resistance to the drugs can and does happen - it merely takes substantially longer than it did before. In addition, many antiretroviral drugs have severe side effects. For both reasons, patients may need to have their drug load adjusted from time to time. While taking antiretroviral drugs, HIV-positive patients must regularly have two blood tests: a Per Viral Load (PVL) test to determine viral levels in the blood, and a CD4+ white blood cell count to determine the relative strength of the immune system. A CD4+ count below 200 cells per mL indicates a patient has progressed to the final stage of the disease, AIDS. In contrast, a very low PVL count (ideally, "undetectable") and a high CD4+ count (above 500 is equivalent to a normal immune system) indicates the disease is being held in check. Note that undetectable does not mean the virus has been eliminated from the body, but it does mean that it has been reduced to levels low enough that the standard blood tests cannot detect it.
Regular checks of both levels are necessary because if the viral load begins to climb and the white blood cell count to fall, it may be an indication that the virus has become resistant to the particular combination of drugs being taken. If resistance to one combination of drugs occurs, then new drugs must be found and used instead.
If you are concerned that you may have contracted HIV, or are seeking medical assistance in managing an HIV infection, you should discuss your concerns with your doctor or (where possible) a sexual health clinic. These sources can offer professional medical advice tailored to your specific situation.
- Sources and More Information -
TheBody.com. "What is Antiretroviral Therapy (ART)?"
World Health Organization. "Antiretroviral Therapy."