The effect of syndromic management interventions on the prevalence of sexually transmitted infections in South Africa

Abstract

Objectives: Few studies have assessed the effect of syndromic management interventions on the prevalence of sexually transmitted infections (STIs) at a population level. This study aims to determine the effect of syndromic management protocols that have been introduced in South Africa since 1994.

Study design: A mathematical model of sexual behaviour patterns in South Africa was used to model the incidence of HIV, genital herpes, syphilis, chancroid, gonorrhoea, chlamydial infection, trichomoniasis, bacterial vaginosis and vaginal candidiasis. Assumptions about health seeking behaviour and treatment effectiveness were based on South African survey data. The model was fitted to available STI prevalence data.

Main outcome measures: Reductions in STI prevalence due to syndromic management.

Results: Between 1995 and 2005, there were significant reductions in the prevalence of syphilis, chancroid, gonorrhoea, trichomoniasis and chlamydial infection. In women aged between 15 and 49, syndromic management resulted in a 33% (95% CI: 23-43%) decline in syphilis prevalence, a 6% (95% CI: 3-11%) reduction in gonorrhoea prevalence, a 5% (95% CI: 1-13%) reduction in the prevalence of bacterial vaginosis and a substantial decline in chancroid. However, syndromic management did not significantly reduce the prevalence of other STIs. For all STIs, much of the modelled reduction in STI prevalence between 1995 and 2005 can be attributed to either increased condom usage or AIDS mortality.

Conclusions: Syndromic management of STIs can be expected to decrease the prevalence of curable STIs that tend to become symptomatic, but has little effect on the prevalence of STIs that are mostly asymptomatic.