Short item Published on September 20, 2010

Modelling the potential impact of age-targeted early HIV treatment initiation in South Africa

At the 3rd Annual Congress of ISPOR South Africa, Wim Delva – senior researcher at SACEMA – gave a presentation on age-targeted early HIV treatment initiation. As reported earlier in the SACEMA Quarterly, universal, immediate antiretroviral treatment (ART) has the potential to reduce HIV incidence dramatically (1). However, this may not be feasible nor affordable for many countries, including South Africa. Therefore, targeting 20-30 year old adults only (age-targeting) might be more efficient.

A mathematical model for the spread of HIV was developed, stratified by age, sex and CD4 cell count to compare the effectiveness and efficiency of universal, immediate ART versus age-targeted, immediate ART. Demographical, behavioural and ART input data were chosen to reproduce the South African HIV epidemic. Effectiveness and efficiency over 10 years (2010 – 2020) were expressed as the reduction in HIV incidence (effectiveness) and the number of averted HIV infections per additional 100 person years of ART (efficiency), relative to the current scenario of ART eligibility at 200 CD4 cells per microliter. The results showed that the HIV incidence in 15-49 year olds is expected to drop by 29% (to a level of 0.8%) in 2020 under the current treatment eligibility criteria. Universal, immediate ART initiation results in an 84% reduction in incidence and 7.3 averted HIV infections per additional 100 person years of ART. For age-targeted early HIV treatment initiation these figures are: 75% reduction and 15.9 averted HIV infections.

In conclusion, the incidence of HIV is likely to drop over the next 10 years due to natural dynamics of the epidemic and a limited effect of the current HIV treatment strategy. Age-targeted earlier ART initiation may have a substantial incremental impact on the incidence of HIV while being more than twice as efficient as universal, immediate ART initiation.