Thembisa is a mathematical model of the South African HIV epidemic, designed to answer policy questions relating to HIV prevention and treatment. Thembisa is also a demographic projection model and a source of demographic statistics. Recently the model has also been extended to include tuberculosis.


‘Thembisa’ means ‘give hope’ in Xhosa and Zulu. The name reflects the optimism that has arisen following major advances in HIV prevention and treatment, and the hope that HIV transmission in South Africa will be substantially curtailed over the next two decades.


Since 2017, Thembisa has been the source on which the official UNAIDS estimates for South Africa are based. The Thembisa developers at the University of Cape Town work in partnership with UNAIDS and the South African Department of Health to produce these estimates.