Nairobi — Extra-couple HIV transmission - infections from sexual intercourse taking place outside an established partnership - continue to fuel new HIV infections among heterosexual couples in Sub-Saharan Africa, according to a study.
In some countries, up to 65 per cent of new infections among men in co-habiting relationships are due to extra-couple intercourse.
Scientists analysed the HIV tests of 27,000 cohabiting couples from 18 African countries. They found extra-couple transmissions to be a common contributing factor for new HIV infections in the region and that the transmissions within couples occur largely from men to women.
For this reason, the authors advocate HIV prevention interventions for the entire sexually active population, not just couples where one partner is HIV-positive.
Sub-Saharan Africa is home to around 22.9 million people living with HIV/AIDS - the majority of the 34 million infected people worldwide - and registers the highest number of HIV-related deaths annually, according to the WHO.
Steve Bellan, a post-doctoral researcher at the University of Texas and the study's lead author, tells SciDev.Net that the research team wanted to identify how many people were infected with HIV before entering their current relationship; how many were infected by their official partner; and how many by extra-couple intercourse.
"Extra-couple transmission within stable, cohabiting couples was responsible for new HIV infections among an overwhelming 32-65 per cent of men and 10-47 per cent of women - varying according to country," Bellan says.
He says that individual country analyses gave wide-ranging results relating to the percentage of transmissions due to extra-couple intercourse.
Bellan was unable to say if the study's findings were typical of Africa only, but he called for further research to enable a comparison of world regions.
The study, published online in The Lanceton 5 February, proposes certain measures to help curb the epidemic, such as early and proper antiretroviral treatments.
Couples should also be offered the opportunity to get tested, receive their results and mutually disclose their status in a supportive counselling environment, the study says, as this will aid treatment and prevention.
It also recommends expanding treatment, whereby all infected individuals should be given immediate early treatment on a 'test and treat concept' basis.
Alloys Orago, director of Kenya's National AIDS Control Council, tells SciDev.Net: "Since 2008, we have been advocating for a reduction in the number of sexual partners and being faithful to a single, uninfected sexual partner as a tool in HIV prevention".
"HIV prevention should target everybody, not just populations perceived to be most at risk, because HIV knows no boundaries," he concludes.