181293 Estimating the proportion of new HIV infections that occur within married/cohabiting couples in urban Zambia and Rwanda

Wednesday, October 29, 2008

Kristin Dunkle, MPH PhD , Rollins School of Public Health and Center for AIDS Research, Emory Univeristy, Atlanta, GA
Rob Stephenson, PhD , Rollins School of Public Health and Center for AIDS Research, Emory University, Atlanta, GA
Etienne Karita, MD MSPH , Projet San Francisco, Kigali, Rwanda
Elwyn Chomba, MD , Project ZEHRP, Emmasdale, Lusaka, Zambia
Kayitesi Kayitenkore, MD MPH , Projet San Francisco, Kigali, Rwanda
Cheswa Vwalika, MD MPH , Project ZEHRP, Emmasdale, Lusaka, Zambia
Susan Allen, MD MPH , Rollins School of Public Health, Emory University, Atlanta, GA
Background: Marriage is increasingly recognized as a potentially high-risk setting for heterosexual HIV transmission, especially for women, but few attempts have been made to estimate the burden of HIV attributable to marital transmission and HIV prevention efforts remain focused on abstinence and non-marital sex.

Methods: We used population-based Demographic and Health Survey data on sexual behaviour and service-based data on HIV serodiscordance among couples in urban Zambia and Rwanda to estimate the proportion of annually incident heterosexual HIV transmission which takes place within married or cohabiting couples in these settings.

Results: Under our base model, we estimate that 55.7% to 92.8% of new heterosexually acquired HIV infections among sexually active adults in urban Zambia and Rwanda occur within serodiscordant marital/cohabiting relationships, depending on sex of the index partner and location. Under our extended model, which considers the higher rates of reported condom use with non-cohabiting partners, we estimate that 60.7% to 94.3% of new heterosexually acquired HIV infections among sexually active adults in these settings occur within heterosexual serodiscordant marital/cohabiting relationships. We estimate that a couples-based intervention which reduced transmission in serodiscordant urban cohabiting couples to 7% per annum could avert 36.1% to 60.3% of HIV infections that would otherwise occur.

Conclusion: The majority of heterosexual HIV transmission for both men and women in urban Zambia and Rwanda takes place within marriage or cohabitation. We therefore call for increased promotion of couples-based voluntary counselling and testing and for development of other evidence-based, culturally and gender-sensitive interventions targeting heterosexual couples.

Learning Objectives:
1. Quantify the proportion of heterosexually acquired HIV infections that take place within married or cohabiting couples in two African capital cities 2. Quantify the proportion of new HIV infections that could be averted by effective couples-based HIV prevention programs in two African capital cities 3. Describe at least three benefits of collecting data on HIV serodiscordance among married/cohabiting couples 4. Explain how publicly available DHS data sets can be harnessed to examine HIV transmission among couples, and list at least two limitations of this data source 5. Articulate at least two benefits of couples VCT over individual VCT

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I co-conceptualized the project, carried out all data analysis and led the drafting of the content.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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