sahr2001 - Health Systems Trust

This model is able to produce output scenarios for differing levels of
change, particularly with respect to HIV risk behaviour and
intervention. The change scenario is included not so much because
this is a likely scenario but in order to break away from the tradition
of only showing what is expected to happen if nothing is done. It
comprises the following assumptions:
• no antiretroviral therapy
• mother-to-child-transmission intervention (phased in from 40% of
births in the year starting 1 July 2001 to 90% in five years time,
and assumed to 50% effective)
• treatment of sexually transmitted diseases (STDs) such that these
are reduced by 15% phased in over the five years starting 1 July
2001
• a doubling in condom usage over the next five years
• a decrease in the number of new sexual partners by 15% over the
next five years.
◆ Another model, referred to as the Metropolitan Life/Doyle model, is
sometimes quoted.
◆ The Institute for Futures Research at the University of Stellenbosch
has provided projections in the form of high, medium and low scenarios.
• High population projections: The demographic impact of HIV/AIDS
is not incorporated, therefore life expectancy at birth increases
throughout the projection period; fertility rates decline steadily;
and a high degree of in-migration (200 000 per annum) is assumed.
• Medium population projections: The impact of the HIV/AIDS
epidemic is incorporated from 2011 onwards; fertility rates in black/
African and coloured women decline more rapidly than in the high
projections; and a medium degree of in-migration (150 000 per
annum) is assumed.
• Low population projections: The impact of the HIV/AIDS epidemic
is incorporated from 1996 onwards; fertility rates are similar to
those of the medium projections; and a low degree of in-migration
(100 000 per annum) is assumed.
Data from the controversial MRC report on the impact of the HIV/AIDS on
mortality were not included since the ASSA2000 data provides more up-todate
projections than the ASSA600 model used in the MRC report. However
the other sources of population projections show general agreement with the
findings reported by the MRC.
The three basic input variables for population projections are fertility,
mortality and migration. The first of these, fertility, is theoretically linked
with socio-economic development - fertility is assumed to decline faster in
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