The South African HIV epidemic, reflected by nine provincial epidemics, 1990-1996

Abstract

Objectives: To determine by serological examination the annual point prevalence rates of infection with the human immunodeficiency virus (HIV) in representative samples of subjects in the nine provinces of South Africa, 1990-1996.

Design: Annual cross-sectional point prevalence surveys conducted in October/November of each year.

Setting: South Africa, including areas that used to be known as self-governing and independent National States.

Subjects: Pregnant women in the age group 15-49 years who attend antenatal clinic services provided by the public health services, and who act as an indicator group of the HIV epidemic among the heterosexually active population.

Outcome measures: HIV positivity as determined serologically; done consistently over several years, this serves to monitor the distribution and trend of the HIV epidemic in each of the nine provinces of South Africa.

Results: Empirical data gained from seven annual, consecutive countrywide surveys demonstrate a wide geographical variation in the point prevalence rates of HIV infection. In October/November 1996 the point prevalence rates (%) were as follows: Western Cape 3.09, Northern Cape 6.57, Northern Province 7.96, Eastern Cape 8.10, Gauteng 15.49, Mpumalanga 15.77, Free State 17.49, KwaZulu-Natal 19.90 and North West 25.13. The weighted national average was 14.17%. There are indications that some of the provinces (KwaZulu-Natal and possibly Mpumalanga) might have passed a point of inflection suggesting deceleration in their specific rates of increase. These results are, however, counterbalanced by the exponential growth still being experienced in provinces with large populations such as Gauteng and the Eastern Cape. It is concluded that the net effect of these divergent trends currently affects the national figure only marginally. A major deflection from the exponential growth patterns seen hitherto can be anticipated only once all or most of the highly populated provinces have traversed their respective points of inflection. The exponential model significantly explains the HIV epidemics in the provinces. The combination of these provincial epidemics describes the initial exponential phase of the epidemic.