Management of HIV/AIDS

The management of HIV/AIDS normally includes the use of multiple antiretroviral drugs in an attempt to control HIV infection. There are several classes of antiretroviral agents that act on different stages of the HIV life-cycle. The use of multiple drugs that act on different viral targets is known as highly active antiretroviral therapy (HAART). HAART decreases the patient's total burden of HIV, maintains function of the immune system, and prevents opportunistic infections that often lead to death. HAART also prevents the transmission of HIV between serodiscordant same sex and opposite sex partners so long as the HIV-positive partner maintains an undetectable viral load.Our results provide a similar level of evidence on viral suppression and HIV transmission risk for gay men to that previously generated for heterosexual couples and suggest that the risk of HIV transmission in gay couples through condomless sex when HIV viral load is suppressed is effectively zero. Our findings support the message of the U=U (undetectable equals untransmittable) campaign, and the benefits of early testing and treatment for HIV. The management of HIV/AIDS normally includes the use of multiple antiretroviral drugs in an attempt to control HIV infection. There are several classes of antiretroviral agents that act on different stages of the HIV life-cycle. The use of multiple drugs that act on different viral targets is known as highly active antiretroviral therapy (HAART). HAART decreases the patient's total burden of HIV, maintains function of the immune system, and prevents opportunistic infections that often lead to death. HAART also prevents the transmission of HIV between serodiscordant same sex and opposite sex partners so long as the HIV-positive partner maintains an undetectable viral load. Treatment has been so successful that in many parts of the world, HIV has become a chronic condition in which progression to AIDS is increasingly rare. Anthony Fauci, head of the United States National Institute of Allergy and Infectious Diseases, has written, 'With collective and resolute action now and a steadfast commitment for years to come, an AIDS-free generation is indeed within reach.' In the same paper, he noted that an estimated 700,000 lives were saved in 2010 alone by antiretroviral therapy. As another commentary in The Lancet noted, 'Rather than dealing with acute and potentially life-threatening complications, clinicians are now confronted with managing a chronic disease that in the absence of a cure will persist for many decades.' The United States Department of Health and Human Services and the World Health Organization recommend offering antiretroviral treatment to all patients with HIV. Because of the complexity of selecting and following a regimen, the potential for side effects, and the importance of taking medications regularly to prevent viral resistance, such organizations emphasize the importance of involving patients in therapy choices and recommend analyzing the risks and the potential benefits. The World Health Organization has defined health as more than the absence of disease. For this reason, many researchers have dedicated their work to better understanding the effects of HIV-related stigma, the barriers it creates for treatment interventions, and the ways in which those barriers can be circumvented. There are six classes of drugs, which are usually used in combination, to treat HIV infection. Antiretroviral (ARV) drugs are broadly classified by the phase of the retrovirus life-cycle that the drug inhibits. Typical combinations include 2 Nucleoside reverse-transcriptase inhibitors (NRTI) as a 'backbone' along with 1 Non-Nucleoside reverse-transcriptase inhibitor (NNRTI), protease inhibitor (PI) or Integrase inhibitors (also known as integrase nuclear strand transfer inhibitors or INSTIs) as a 'base.' Entry inhibitors (or fusion inhibitors) interfere with binding, fusion and entry of HIV-1 to the host cell by blocking one of several targets. Maraviroc and enfuvirtide are the two currently available agents in this class. Maraviroc works by targeting CCR5, a co-receptor located on human helper T-cells. Caution should be used when administering this drug, however, due to a possible shift in tropism which allows HIV to target an alternative co-receptor such as CXCR4. In rare cases, individuals may have a mutation in the CCR5 delta gene which results in a nonfunctional CCR5 co-receptor and in turn, a means of resistance or slow progression of the disease. However, as mentioned previously, this can be overcome if an HIV variant that targets CXCR4 becomes dominant. To prevent fusion of the virus with the host membrane, enfuvirtide can be used. Enfuvirtide is a peptide drug that must be injected and acts by interacting with the N-terminal heptad repeat of gp41 of HIV to form an inactive hetero six-helix bundle, therefore preventing infection of host cells. Nucleoside reverse-transcriptase inhibitors (NRTI) and nucleotide reverse-transcriptase inhibitors (NtRTI) are nucleoside and nucleotide analogues which inhibit reverse transcription. HIV is an RNA virus and hence unable to become integrated into the DNA in the nucleus of the human cell; it must be 'reverse' transcribed into DNA. Since the conversion of RNA to DNA is not done in the mammalian cell it is performed by a viral protein which makes it a selective target for inhibition. NRTIs are chain terminators such that once incorporated, work by preventing other nucleosides from also being incorporated into the DNA chain because of the absence of a 3' OH group. Both act as competitive substrate inhibitors. Examples of currently used NRTIs include zidovudine, abacavir, lamivudine, emtricitabine, and tenofovir. Non-nucleoside reverse-transcriptase inhibitors (NNRTI) inhibit reverse transcriptase by binding to an allosteric site of the enzyme; NNRTIs act as non-competitive inhibitors of reverse transcriptase. NNRTIs affect the handling of substrate (nucleotides) by reverse transcriptase by binding near the active site. NNRTIs can be further classified into 1st generation and 2nd generation NNRTIs. 1st generation NNRTIs include nevirapine and efavirenz. 2nd generation NNRTIs are etravirine and rilpivirine. HIV-2 is naturally resistant to NNRTIs.