Spatial variations in STIs among women enrolled in HIV prevention clinical trials in Durban, KwaZulu-Natal, South Africa

Abstract

South Africa is faced with a high HIV and STI prevalence and incidence, respectively, with pockets of high burden areas driving these  diseases. Localised monitoring of the HIV epidemic and STI endemic would enable more effective targeted prevention strategies. We assessed spatial variations in curable STI incidence among a cohort of women enrolled in HIV prevention clinical trials between 2002 and  2012. STI incidence rates from 7557 South African women enrolled in five HIV prevention trials were geo-mapped using participant household GPS coordinates. Age and period standardised incidence rates were calculated for 43 recruitment areas and Bayesian  conditional autoregressive areal spatial regression (CAR) was used to identify significant patterns and spatial patterns of STI infections in recruitment communities. Overall age and period standardised STI incidence rate were estimated as 15 per 100 PY and ranged from 6 to  24 per 100 PY. We identified five significant STI high risk areas with higher-than-expected incidence of STIs located centrally (three- locations) and southern neighbouring areas of Durban (two-locations). Younger age (<25), not married/cohabitating, parity <3 and poor  education were all significant correlates of high STI communities. Findings demonstrate sustained STI incidence rates across the greater  Durban area. The role of STI incidence in HIV acquisition in high HIV endemic areas need to be revisited as current highly effective PrEP  interventions do not protect from STI acquisition. In these settings there is an urgent need for integrative HIV and STI prevention and  treatment services.