Definition of the Prevention Area
HIV-serodiscordant couples, in which one partner is HIV-positive and the other is HIV-negative, are now recognized as a priority for HIV prevention interventions.
Epidemiological Justification for the Prevention Area
Although there is considerable variation across countries, recent studies of mature epidemics in sub-Saharan Africa show that up to two-thirds of couples dealing with HIV are discordant. These studies assessed the extent to which HIV transmission within marriages was spurred by high rates of HIV among heterosexual couples in sub-Saharan Africa. One analysis estimated that 55 to 92 percent of new, heterosexually acquired HIV infections among adults occurred within serodiscordant marital or cohabiting relationships. Additionally, among discordant couples, only the female partner was infected in 30 to 40 percent of cases, which contradicts the common perception that only men, not women, are the HIV-positive partner.
According to a research review, the following factors make it more likely that a person living with HIV will transmit the virus to his or her partner: the presence of other sexually transmitted infections, particularly genital ulcerative diseases; high viral load; failure to use condoms correctly and consistently; and specific sexual practices, such as a high number of sexual partners and higher frequency of sexual contact. Concurrent sexual partnership may also contribute to risk. The risk of transmission is especially high during early infection, when the virus is estimated to be 26 times more infectious than during later stages of infection. This makes it especially important to identify HIV infection during the early, acute stage.
Prevention responses also need to take into account the progress of the epidemic. One hypothesis is that in early epidemics, discordancy in most couples arises due to HIV infection of one partner through a pre-existing relationship, whereas in more mature epidemics, a greater proportion of HIV-negative partners initiate relationships with a new partner who is already infected.
Core Programmatic Components
HIV prevention programs among discordant couples are traditionally based on three types of interventions: 1) couples HIV testing services (HTS)—both through community-based outreach and antenatal clinics; 2) group-based workshops with serodiscordant couples; and 3) integrated antiretroviral therapy (ART) and HIV prevention programs. These programs often include risk reduction counseling, referrals to treatment, counseling on family planning, and an avenue to further care and support services.
Couples HTS is the cornerstone of many discordant couple interventions; it remains the only way to identify couples in which one partner is HIV-positive and one is HIV-negative. New and innovative methods are being developed to increase uptake of couples HTS, since many individuals and couples do not know their status. To increase HTS uptake among couples, programs will likely need to integrate the couples testing with broader HIV programs including care, treatment, and support services; mother-to-child-transmission programs; male circumcision; condom promotion; partner reduction; and other behavior change interventions.
Effective prevention programming is necessary for serodiscordant couples, targeted both to the couple and to the individuals. One study showed that the HIV-negative partner increased the number of their outside sexual partners after learning their partner's HIV-positive status. Campbell et al (2011) confirmed this result, showing that about 27 percent of seroconverters in serodiscordant couples in the study were infected by an outside partner.
New advances in the biomedical field (pre-exposure prophylaxis and ART as prevention) have demonstrated success in reducing HIV transmission among discordant couples. These prevention methods are included in the World Health Organization guidelines on the use of antiretroviral drugs for treating and preventing HIV infection.
Current Status of Implementation Experience
Programs in developing countries aimed at reducing transmission of HIV in discordant couples are too new to evaluate for effectiveness. To date, interventions have largely been conducted within structured research protocols. It is still uncertain whether the efficacy of such interventions will work in real-life settings, and whether they can be scaled up to achieve sufficient reach to reduce rates of HIV transmission at the population level.