One of the main reasons for the HIV epidemic in sub-Saharan Africa is the sheer number of heterosexual couples having intercourse with people outside their partnership.

A study published in The Lancet indicates that current anti-HIV strategies which focus solely on couples in which one member is infected with HIV, might not be enough to decrease the prevalence of HIV in the region.

Leader of the study, Steve Bellan from the University of Texas, Austin, said:

“Because of the large contribution of extra-couple transmission (from outside partnerships) to new HIV infections, interventions should target the larger sexually active population and not just serodiscordant couples.

Pre-couple (prior to relationship), extra-couple, and within-couple transmission are all common, and HIV control policies that address all these routes are needed to stem the HIV epidemic in Africa.”

Sub-Saharan Africa is an area with an ever-growing HIV problem, and targeting the groups at high risk of contracting the infection is crucial for intervention strategies. The proportion of transmission of the disease by heterosexual couples versus single people continues to cause much debate among experts.

Researchers created a complex modeling system that combined serostatus and relationship data from Demographic and Health Surveys (DHS). This model helped identify the routes by which people from 27,201 cohabiting couples became infected with HIV in the sub-Saharan region.

The results showed that 30-65% of HIV infections in men and 10-47% in women – who were in a stable relationship with their partners – were caused by extra-couple transmission.

Interestingly, the study also revealed that the majority of transmissions in couples occurs from men to women rather than from women to men. Women were found to be at a high risk of infection before entering a cohabiting relationship.

Connie Celum and Jared Baeten from the University of Washington add:

“HIV prevention for only HIV serodiscordant couples will not be enough to reverse the HIV epidemic completely. HIV prevention is at a crucial stage: strategies to deliver evidence-based combination prevention efficiently and effectively, targeted at high risk populations and with high coverage for those at risk, will maximise this incredible opportunity in the history of the HIV epidemic.”

Previous interventions have provided HIV testing at African homes as well as voluntary counseling, these have managed to increase awareness of HIV status among those who are undiagnosed.

Written by Joseph Nordqvist