Can highly active antiretroviral therapy reduce the spread of HIV?: A study in a township of South Africa

Abstract

Background: Calls have been made for the large-scale delivery of highly active antiretroviral therapy (HAART) to people infected with HIV in developing countries. If this is to be done, estimates of the number of people who currently require HAART in high HIV prevalence areas of sub-Saharan Africa are needed, and the impact of the widespread use of HAART on the transmission and, hence, spread of HIV must be assessed.

Objectives: To estimate the proportion of people eligible for combination antiretroviral therapy and to evaluate the potential impact of providing HAART on the spread of HIV-1 under World Health Organization (WHO) guidelines in a South African township with a high prevalence of HIV-1.

Design: A community-based cross-sectional study in a township near Johannesburg, South Africa, of a random sample of approximately 1000 men and women aged 15 to 49 years.

Methods: Background characteristics and sexual behavior were recorded by questionnaire. Participants were tested for HIV-1, and their CD4 cell counts and plasma HIV-1 RNA loads were measured. The proportion of people whose CD4 cell count was less than 200 cells/mm and who would be eligible to receive HAART under WHO guidelines was estimated. The potential impact of antiretroviral drugs on the spread of HIV-1 in this setting was determined by estimating among the partnerships engaged in by HIV-1-positive individuals the proportion of spousal and nonspousal partnerships eligible to receive HAART and then by calculating the potential impact of HAART on the annual risk of HIV-1 transmission due to sexual contacts with HIV-1-infected persons. The results were compared with those obtained using United States Department of Health and Human Services (USDHHS) guidelines.

Results: The overall prevalence of HIV-1 infection was 21.8% (19.2%-24.6%), and of these people, 9.5% (6.1%-14.9%) or 2.1% (1.3%-3.3%) of all those aged 15 to 49 years would be eligible for HAART (ranges are 95% confidence limits). In each of the next 3 years 6.3% (4.6%-8.4%) of those currently infected with HIV-1 need to start HAART. Among the partnerships in which individuals were HIV-1-positive, only a small proportion of spousal partnerships (7.6% [3.4%-15.6%]) and nonspousal partnerships (5.7%, [3.0%-10.2%]) involved a partner with a CD4 cell count below 200 cells/mm and would have benefited from the reduction of transmission due to the decrease in plasma HIV-1 RNA load under HAART. Estimates of the impact of HAART on the annual risk of HIV-1 transmission show that this risk would be reduced by 11.9% (7.1%-17.0%). When using USDHHS guidelines, the proportion of HIV-1-positive individuals eligible for HAART reached 56.3% (49.1%-63.2%) and the impact of HAART on the annual risk of HIV-1 transmission reached 71.8% (64.5%-77.5%).

Conclusions: The population impact of HAART on reducing sexual transmission of HIV-1 is likely to be small under WHO guidelines, and reducing the spread of HIV-1 will depend on further strengthening of conventional prevention efforts. A much higher impact of HAART is to be expected if USDHHS guidelines are used.

Figure 1

Distribution of CD4+ cell count among HIV-1-infected persons (with the upper limit of the 95% confidence interval).

Figure 2

Plasma HIV-1 RNA load by CD4+ count among HIV-1-positive individuals. The regression line is plasma HIV-1 RNA load (copies/ml − log10) = 5.40 − 1.57 10⁻³ CD4+ count (Spearman’s ρ = − 0.53, p = 0.000).