Health Care Management Science

, Volume 17, Issue 2, pp 182–193

The importance of extended high viremics in models of HIV spread in South Africa

  • Benjamin Armbruster
  • Ekkehard C. Beck
  • Mustafa Waheed

DOI: 10.1007/s10729-013-9245-z

Cite this article as:
Armbruster, B., Beck, E.C. & Waheed, M. Health Care Manag Sci (2014) 17: 182. doi:10.1007/s10729-013-9245-z


Recent studies found a substantial fraction of ‘extended high viremics’ among HIV-1 subtype C, the most common subtype in southern Africa. Extended high viremics are HIV infected individuals who maintain a high viral load for a longer time period than usual after the initial infection. They are more infectious during this period, and their infection progresses to full-blown AIDS and death much faster than usual. This study investigates the impact of extended high viremics on the spread of the HIV epidemic in South Africa. We develop a simple deterministic compartmental model for HIV infection that includes extended high viremics. As the available data on extended high viremics are limited, we parameterize this model using only the fraction of extended high viremics among new infections and the reduced life-span of extended high viremics. We find that without extended high viremics, the HIV prevalence in South Africa would have remained close to its 1990 level, instead of increasing to the current epidemic levels. We also find that the greater the fraction of extended high viremics among susceptibles, the greater the steady-state HIV prevalence and the more sensitive the steady-state prevalence is to the HIV transmission probability. These results suggest that extended high viremics have an impact on the HIV epidemic in South Africa; justify the need for comprehensive epidemiological studies since the current data is limited; and suggest that future models of HIV for southern Africa should explicitly model extended high viremics.


Extended high viremics HIV transmission HIV epidemic Southern Africa HIV Compartmental model 



Human immunodeficiency syndrome


Ribonucleic acid


Center for HIV Vaccine Immunology


Antiretroviral therapy


Acquired immunodeficiency syndrome


Men who have sex with men


Preexposure prophylaxis


Injection drug user


Highly active antiretroviral therapy

MSC codes

92D30 92B05 

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Benjamin Armbruster
    • 1
  • Ekkehard C. Beck
    • 1
  • Mustafa Waheed
    • 1
  1. 1.Department of Industrial Engineering and Management SciencesNorthwestern UniversityEvanstonUSA

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