Effect of concurrent sexual partnerships on rate of new HIV infections in South Africa.

Concurrent sexual partnerships are widely believed to be one of the main drivers of the HIV epidemic in sub-Saharan Africa based on theoretical models, but the effect of concurrent partnerships on HIV incidence has not actually been studied in sub-Saharan Africa. This study, a population-based cohort study, used data from an ongoing demographic surveillance site in KwaZulu-Natal, South Africa, on estimated prevalence of partnership concurrency (range 4-76.3%; mean 31.5%) and number of lifetime sexual partners (3.4-12.9; mean 6.3) among 2,153 men. The study assessed incident infections in women in association with the number of partners and rate of concurrency reported by men in the area and used this to quantify the effect of the men's sexual behaviour on a woman's risk of getting HIV.

The study found that mean lifetime number of partners of men in the immediate local community was predictive of risk of HIV acquisition in women, whereas a high prevalence of partnership concurrency in the same local community was not associated with any increase in risk of HIV acquisition. The researchers therefore called for unambiguous messages about the need to reduce multiple partnerships, whether they overlap in time or not. (1)

(1.) Tanser F, Barnighausen T, Hund L, et al. Effect of concurrent sexual partnerships on rate of new HIV infections in a high-prevalence, rural South African population: a cohort study. Lancet 20l1;378:247-55.

DOI: 10.1016/S0968-8080(11)38588-6