By Deirdre Kelly, PhD
Globally, 34 million people are HIV-positive, the majority (69%) of which live in Sub-Saharan Africa where 1 in 20 adults live with this immunocompromising infection. Other epicentres of this disease include South, South-East and East Asia, Eastern Europe and the Caribbean. HIV infection rates are falling however, with 2.5 million infections in 2011 a 20% reduction compared to 2001. HIV/AIDS-related deaths are also in decline, where 1.7 million were reported in 2011, a 24% decrease since 2005. The majority (70%) of these fatalities were located in Sub-Saharan Africa. The reason that there has been such a dramatic reduction in HIV/AIDS related deaths is an increase in antiretroviral therapy (ART) in low- and middle-income countries. In the last 18 years, ART has saved 14 million lives.
Current World Health Organization ART guidelines indicate that patients with a CD4 threshold of 500 cells/mm3 or less for adults, adolescents and older children should begin treatment. However in pregnant or breast-feeding women, children less than five years and patients with co-infections such as tuberculosis and hepatitis B or co-morbidities, ART treatment can be initiated regardless of CD4 count. The US Department of Health and Human Services currently recommends the following ART regimes for treatment naïve HIV patients, in order of FDA approval:
• Efavirenz/tenofovir disoproxil fumarate/emtricitabine (EFV/TDF/FTC)
• Ritonavir-boosted atazanavir + tenofovir disoproxil fumarate/emtricitabine (ATV/r + TDF/FTC)
• Ritonavir-boosted darunavir + tenofovir disoproxil fumarate/emtricitabine (DRV/r + TDF/FTC)
• Raltegravir + tenofovir disoproxil fumarate/emtricitabine (RAL + TDF/FTC)
In order to determine the success of ART regimes, patients undergo viral load testing as well as clinical and immunological monitoring. CD4-count point-of-care testing is also currently available. A number of genotypic resistance assays are also available to determine genetic basis of viral strain and subsequently aid selection of ART regimes. These assays indicate whether the virus is resistant to to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and/or protease inhibitors (PIs). HIV genotype assays are important to determine if a patient has a strain that can confer drug resistance. Some commercial labs also provide integrase and fusion inhibitor resistance testing. Current guidelines also indicate that if a CCR5 antagonist is considered as potential therapy, a co-receptor tropism assay should be carried out. HIV genotype assays are important to determine if a patient has a strain that can confer drug resistance.
By 2015 UNAIDS aims to provide ART to 15 million people globally and reduce HIV transmission (sexual contact and Intravenous) by 50%. According to Michel Sidibé, UNAIDS Executive Director, Under Secretary-General of the United Nations, the organisation also aims to reduce the number of HIV-TB deaths by 50% and obtain global investments of US$ 22 billion in low- and middle-income countries annually. This will in turn reduce HIV burden and fatalities and improve the life expectancy of HIV-positive individuals.
- UNAIDS Report on the global AIDS epidemic 2012 (November 2012)
- Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of
antiretroviral agents in HIV-1-infected adults and adolescents. Department of Health and
Human Services. Available at http://aidsinfo.nih.gov/ContentFiles/Adultand
AdolescentGL.pdf. Section accessed 10th August 2013
- World Health Organization Consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection