Since most heterosexual HIV transmission for both men and women in urban Zambia and Rwanda takes place within marriage or cohabitation, counselling and testing for couples should be promoted, as should other evidence-based interventions that target heterosexual couples. These are the conclusions of authors of an Article in this week's edition of The Lancet.
Sub-Saharan Africa has a well-documented and high rate of HIV infection, most of which is attributable to heterosexual transmission. Few attempts have been made to assess the extent of HIV transmission within marriages, and HIV-prevention efforts remain focused on abstinence and non-marital sex.
Dr Kristin Dunkle, Rollins School of Public Health, Emory University, Atlanta, GA, USA, and colleagues across Zambia and Rwanda, used population data from Demographic Health Surveys on heterosexual behaviour in Zambia 2001/02 and Rwanda in 2005. They also used data on the HIV joint status of married or cohabiting couples and non-cohabiting couples in Lusaka, Zambia, and Kigali, Rwanda. They estimated the probability that an individual would acquire an incident HIV infection from a cohabiting or non-cohabiting partner, and then the proportion of total heterosexual HIV transmission which likely occurs within married or cohabiting couples in these settings each year.
The researchers analysed data from 1739 Zambian women, 540 Zambian men, 1176 Rwandan women, and 606 Rwandan men. Using modelling they estimated that 55-93% of new heterosexually acquired HIV infections among adults in urban Zambia and Rwanda probably occur within marital or cohabiting couples, with slight variations between women and men and between Zambia and Rwanda. When they extended their model to include higher rates of condom use reported in non-cohabiting partners, the estimate of new heterosexually acquired HIV infections occurring within marital or cohabiting couples went up to 60-94%. HIV transmission in non blood-related couples who are both unaware of their HIV status is estimated to be 20% each year. The researchers estimated than an intervention for couples which reduced this transmission in cohabiting couples from 20% to 7% each year, as observed in couples counselling studies in Zambia, could avert between 36-60% of heterosexually transmitted HIV infections that would otherwise occur.
The authors conclude: "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."
In an accompanying Comment, Dr Rebecca Bunnell, Global AIDS Program, Centers for Disease Control and Prevention-Kenya, Nairobi, Kenya and Dr Peter Cherutich, National AIDS/STD Control Programme, Ministry of Health, Nairobi, Kenya, say: "The findings by Dunkle and colleagues are an urgent call to governments and programmes for HIV prevention, care, and treatment throughout the continent to truly scale up HIV testing with an emphasis on couples and a goal of universal coverage. Definition, standardisation, and implementation of a complete package for efficacious couple-based interventions for all types of couples for HIV prevention and care, including antiretroviral therapy and circumcision, will further decrease HIV transmission within the largest population group at risk within sub-Saharan Africa."
Dr Kristin Dunkle, Rollins School of Public Health, Emory University, Atlanta, GA, USA currently in South Africa T) +27 82 721 8345 E) kdunkle@sph.emory.edu
Dr Rebecca Bunnell, Global AIDS Program, Centers for Disease Control and Prevention-Kenya, Nairobi, Kenya T) +254-724-256-809 E) rrb7@cdc.gov
http://multimedia.thelancet.com/pdf/press/HIV.pdf
Journal
The Lancet