Background:  ART is now becoming available in South Africa, and South Africa has more people living with HIV/AIDS (PLWHA) than any other country. KwaZulu-Natal is the South African province with the largest population (9.4 million) and the highest prevalence of PLWHA (~21% of all South African cases). The majority (56%) of the population of KwaZulu-Natal live in rural communities where the prevalence of HIV is less than in urban areas (9% vs ~13%). In April 2004, the South African government launched a strategic treatment plan for HIV/AIDS. Their first-line drug regime consists of stavudine (d4T), lamivudine (3TC), and efavirenz (EFV), with nevirapine (NVP) replacing EFV for pregnant women. The government plans to treat ~500,000 people in KwaZulu-Natal by 2008, with numbers treated increasing approximately quadratically with time. Demand will exceed supply; thus, decisions will have to be made in allocating ART. The majority of those who will receive treatment will likely be in cities, because health infrastructure and personnel are concentrated in urban centers.

Methods:  Here, we investigate the epidemiological effect of ART (due to different drug allocation strategies) by using a novel mathematical model that includes spatial heterogeneity and linked urban-rural HIV epidemics. Our model is parameterized using data from the South African province of KwaZulu-Natal. We model the South African Government’s treatment plan from 2004 to 2008 and predict the epidemiological consequences of 4 ART allocation strategies:  3 strategies allocate drugs to both urban and rural areas, and 1 strategy allocates drugs only to Durban. All 4 strategies would treat 500,000 people by 2008.

Results:  Surprisingly, we show that the greatest epidemic-level benefits accrue if ART is allocated only to Durban. This strategy (in comparison with the urban-rural strategies) prevents the greatest number of infections by 2008 (an additional 15,000 in comparison with other strategies), minimizes transmitted resistance, and averts the greatest number of AIDS deaths.

Conclusions:  However, this urban-only strategy does not provide an equitable distribution of ART between urban and rural regions, and hence exacerbates health care discrepancies.