Married or cohabiting couples transmit HIV to each other

In urban Zambia and Rwanda, heterosexual HIV transmission in both men and women takes place within marriage or cohabitation, according to an article published in The Lancet. As a result, public policy should promote couples' testing and counseling as well as other evidenced-based interventions.

The study, led by Kristin Dunkle, Rollins School of Public Health, Emory University, Atlanta, GA, USA, and colleagues across Zambia and Rwanda, attempted to analyze the levels of HIV transmission within marriages, to assess if HIV-prevention methods should continue to focus on abstinence and non-marital sex.

The authors used population data from the Demographic Health Surveys in Zambia between 2001 and 2002, and Rwanda in 2005. This was combined with HIV joint status data of married or cohabiting couples and non-cohabiting couples in Lusaka, Zambia, and Kigali, Rwanda. Data was acquired from 1739 Zambian women, 540 Zambian men, 1176 Rwandan women, and 606 Rwandan men.

Using data modelling techniques, they estimated that 55-93% of new heterosexually acquired HIV infections probably occur within married or cohabiting couples. When the model was extended to include the higher rates of condom use that are reported in non-cohabiting partners, this implied that the new heterosexually acquired HIV infections in marital or cohabiting couples would be 60-94% higher.

The transmission of HIV in cohabiting couples who do not know HIV status is estimated to be 20% per year. An intervention for these couples, which has previously reduced transmission in cohabiting couples from 20% to 7% each year in Zambia, could prevent between 36% and 60% of heterosexually transmitted HIV infections that might otherwise occur.

In conclusion, the authors state that new policy should now focus on married and cohabiting heterosexual partners. "Since most heterosexual HIV transmission for both men and women in urban Zambia and Rwanda takes place within marriage or cohabitation, voluntary counselling and testing for couples should be promoted, as should other evidence-based interventions that target heterosexual couples."