How Discordant Couples and HIV Vaccine Research Benefit from Each Other

While IAVI’s mission is to ensure the development of a safe, effective HIV vaccine, the development process itself offers more immediate-term benefits for to those groups like discordant couples who are most in need. IAVI and partners have helped discordant couples to lower their rates of transmission through education, healthcare and prevention efforts that ultimately result in their ability to live fuller, healthier lives, and reduce the spread of HIV/AIDS to others. At the same time, discordant couples have helped researchers gain unique insights into the early stages of HIV transmission and infection that is critical for the development of an HIV vaccine.

In 2003, an estimated 70 percent to 90 percent of HIV infections in southern Africa occurred in married or cohabitating couples who did not realize that one partner was HIV infected and the other was not1 – making transmission in these discordant couples a major contributor to the spread of HIV/AIDS in sub-Saharan Africa2

discordant 1 300pxIAVIHistorically, HIV prevention beginning in the late ‘80s often focused on risk in casual relationships outside of marriage or stable partnerships, as these relationships were often seen as a safe haven. HIV testing and prevention efforts within couples who had been married or living together for a long time already, held little importance despite their high risk of HIV transmission. Moreover, information on strategies to sustain relationships and make sexual and reproductive choices while maintaining health and avoiding HIV transmission were also quite limited.  But the work of the Rwanda Zambia HIV Research Group (RZHRG) set out to change this, and in 2008, a Lancet study concluded an intervention that could reduce transmission for discordant urban cohabiting couples in Zambia and Rwanda from 20% to 7% every year could avert 35.7% to 60.3% of heterosexually transmitted HIV infections that would otherwise occur3

Today, the difficult day-to-day reality for discordant couples continues to realize bright spots of change, in part as a result of RZHRG and HIV vaccine research studies efforts sponsored by IAVI throughout the past twelve years. RZHRG’s work with discordant couples has contributed to a wide range of health and transmission reducing strategies tailored to their needs and fertility intentions including Couples HIV Testing and Counseling (CHTC), disclosure of HIV test results, condom promotion, antiretroviral therapy (ART) for the HIV-infected partner, contraceptive use or safe conception strategies and the use of ART as pre-exposure prophylaxis (PrEP) by the HIV-uninfected partner4.

From 2003-2012, IAVI supported Project San Francisco’s (PSF) work with discordant couples in Kigali, Rwanda, where 3.1% of all married or cohabitating couples were known to be discordant5 This effort, built on work initiated by PSF’s Susan Allen and Etienne Karita in 1986, is recognized as the earliest, longest-standing and largest heterosexual HIV-discordant couples’ group in the world. IAVI supported PSF efforts to translate results of scientific research into policy directed at the needs of discordant couples in local communities. Through close links with government officials and policymakers, PSF advocacy, research and evidence led the Rwandan government to officially recognize the importance of discordant couple interventions to tackle its HIV epidemic.

With IAVI’s support, PSF also contributed to Rwanda’s nationwide spread of couples testing and helped shape national Couples Voluntary Counseling and Testing (CVCT) policy. Well-implemented CVCT is proven to reduce the transmission of HIV by more than two-thirds among those couples who do not share the same HIV status6  Voluntary HIV Counseling and Testing (VCT) programs typically place a focus on testing individuals. By failing to test couples together, traditional testing often misses a critical opportunity for HIV prevention in one of Africa’s largest risk groups – long-term, cohabiting couples7  CVCT includes testing couples and sharing the results with the partners together. Counselors work with the couples to develop a plan to protect each other, depending on whether the couple is concordant (those who share the same results) or discordant (those having different test results). Counseling and testing together builds respect, confidence and commitment within relationships. When people know their HIV status and their options in coping with this situation, they are in a better position to make informed decisions about prevention, sexual behavior and family planning.

PSF, with support from IAVI, has been a leader in promoting CVCT in Africa. In fact, Rwanda’s pioneer implementation of CVCT on a national scale is based on data and advocacy from PSF. Initially, PSF services included on-site couple's voluntary counseling and testing facilities, medical clinic, laboratory and pharmacy – work now owned and sustained by Rwandan government-run clinics that have been trained by PSF staff.

discordant 2 300pxIAVIThese clinics have in turn acted as entry points into numerous IAVI/PSF observational studies to better understand the HIV/AIDS epidemic and clinical trials to investigate the efficacy and safety of vaccine candidates over the past decade. With IAVI support, PSF has worked to engage influential community leaders – such as clergy, clinic staff, traditional healers, birth attendants and policy leaders – to advocate for CVCT and to help increase demand for services on the basis that it has proven to be relatively cheap and effective. PSF now conducts training with other IAVI-affiliated sites as well as with other African health workers and researchers in more than 20 other countries, including countries outside of Africa. The number of requests for training continues to grow, mirroring a corresponding interest in effective and inexpensive prevention methods.

The PSF-led and IAVI-supported discordant couple study has also proved invaluable in adding to critical knowledge about HIV immuno-pathogenesis, the process leading to AIDS following HIV infection that informs vaccine development. These couples offer a rare opportunity to better understand the complex interaction between HIV and the immune system immediately after infection, how the immune system appears to control the initial burst of virus, how HIV changes and escapes from immune defenses, and what virus characteristics allow it to establish persistent infection. In 2010, an IAVI supported study with the Zambia Emory HIV Research Project (ZEHRP) focused on HIV transmission within discordant couples in Lusaka, Zambia. The study, specifically aimed at HIV-1 discordant cohabiting heterosexual couples with subsequent intra-couple (epidemiologically linked) HIV-1 transmission, led to important findings about transmission. The study showed preventative or therapeutic approaches that even marginally reduce viral replication capacity may lower the overall transmission rates and offer long-term benefits even upon transmission8 Most recently, an IAVI-supported discordant couple study and offered insight into ART to further prevention efforts9 The findings support the WHO’s recommendation to put both partners in all discordant couples on ART, regardless of CD4+ T-cell count, to both lower their viral load and the likelihood of transmission.

More than 30 years into the epidemic, it is clear that a vaccine, in combination with proven prevention and treatment tools, is essential to achieving and sustaining the end of AIDS. While a vaccine still remains to be developed, groups like discordant couples who are most in need have already benefited from the research efforts, and they have been helping to ensure that these efforts will succeed in the end.


1 Allen, S., J. Meinzen-Derr, M. Kautzman, I. Zulu, S. Trask, U. Fideli, R. Musonda, F. Kasolo, F. Gao & A. Haworth. 2003. ‘Sexual Behavior of HIV Discordant Couples after HIV Counseling and Testing.’ AIDS 17 (5): 733–740.

2 El-Sadr, W.M., B.J. Coburn, & S.M. Blower. 2011. ‘Modeling the Impact on the HIV Epidemic of Treating scordant Couples with Antiretrovirals to Prevent Transmission.’ AIDS 25(18):2295–9.

3 Lancet. 2008 Jun 28;371(9631):2183-91. doi: 10.1016/S0140-6736(08)60953-8. New heterosexually transmitted HIV infections in married or cohabiting couples in urban Zambia and Rwanda: an analysis of survey and clinical data. Dunkle KL1, Stephenson R, et al.

4 Kathryn Curran, MHS, Jared M. Baeten, MD PhD, Thomas J. Coates, PhD, Ann Kurth, CNM PhD, Nelly R. Mugo, MBChB MMed MPH, and Connie Celum, MD MPH,

5 El-Sadr et al. 2011

6 Ingabire et al. 2013

7 El-Sadr, 2011.

8 Carlson JM, Schaefer M, Monaco DC, et al. Selection bias at the heterosexual HIV-1 transmission bottleneck. Science (New York, NY). 2014;345(6193):1254031. doi:10.1126/science.1254031

9 Karita E, Price M. et al. [The IAVI Africa HIV Prevention Partnership] High Transmitter CD4+ T-Cell Count Shortly after the Time of Transmission in a Study of African Serodiscordant Couples August 20, 2015 DOI: 10.1371/journal.pone.0134438