HIV Pharmacology

In 2020, 37.7 million people globally were living with HIV. With access to anti-retroviral therapy (ART) having dramatically expanded in the last decade, 28.2 million individuals were accessing treatment as of June 2021. Of the 20.7 million people living with HIV/AIDS (PLWHA) in Eastern and Southern Africa, approximately 15 million are on treatment (UNAIDS, 2021).

The increased access to ART has led to substantial improvement in the life expectancy of patients infected with HIV, which is now treated as a chronic disease requiring life-long ARV treatment. HIV is a rolling science and the disease landscape is constantly changing. South Africa remains one of the countries with the highest burden of HIV, with 13.7% of the total population being HIV positive (STATS SA 2021). Access to ART has increased significantly over the last 20 years in the country through multiple landmark events:

  • 2004: ART programme officially begins through the Operational Plan for Comprehensive HIV and AIDS Care, Management and Treatment for South Africa. Accredited service points in all districts provide ARVs, covering only 5% of the country’s public healthcare facilities
  • 2006: National Strategic Plan for HIV & AIDS and STIs (2007-2011) implemented, increasing government provision of ARVs
  • 2009: Launch of National HIV Counselling and Testing campaign, with all public health facilities prepared to provide ARVs
  • 2010: National Department of Health revises ART guidelines to expand and include treatment to all children under 1 year, all pregnant women regardless of CD4+ count and all TB-HIV co-infected patients with a CD4+ count of <350 cells/μl, and changing ART for both first- and second-line therapy to make it safer
  • 2011: National Strategic Plan for HIV & AIDS (2012-2016) launched, with strong focus on key populations
  • 2012: National ART guidelines updated to increase the initiation threshold of ART to 350 cells/μl for all adults, as well as to expand access thresholds for children, introducing fixed-dose combinations
  • 2015: ART initiation threshold updated to CD4<500 cells/μl
  • 2016: Introduction of universal ‘Test and Treat’.
  • 2017: National guidelines shift towards same-day test and treat.
  • 2019: INSTI Dolutegravir replaces Efavirenz in first line and use in second line ART

There are multiple classes of ART used to maintain the health of an HIV infected individual (see Table­ below). Different modes of action allow more than one ARV to be used in combination with other ARVs. Although HIV infection cannot be cured, the combination of ARV drugs allows for the successful control of the infection for many years. The life cycle of HIV, which these drugs interfere with, is discussed more in detail later in this section.