In Canada, an estimated 83% of new HIV infections in 2008 occurred through sexual transmission, either among men who have sex with men (47%) or heterosexual men and women (36%). Among both groups a large number of these sexual HIV transmissions likely took place in the context of intimate relationships.
However, HIV prevention efforts in Canada focus mostly on changing the behaviour of an individual and often neglect the critical role partners may play in HIV transmission. Neglecting partners in HIV testing and counselling may be a missed opportunity for HIV prevention and treatment in Canada.
The World Health Organization (WHO) recently released "Guidance on Couples HIV Testing and Counselling," which outlines the important role of HIV testing and counselling for couples in HIV prevention, treatment and care.
The guidelines encourage countries to increase the offering of HIV testing and counselling to couples in addition to support for mutual disclosure of HIV status. In the guidelines, the WHO also recommends offering antiretroviral treatment to serodiscordant couples (in which one partner is HIV-positive and the other is HIV-negative) regardless of CD4 count in order to prevent HIV transmission.
The guidelines outline several potential benefits of offering HIV testing and counselling, along with support for mutual disclosure of HIV status, to couples. Many of these benefits are relevant to all couples, including those in which both partners are HIV-negative or both are HIV-positive.
In Canada, many people are unaware of their partner's, or their own, HIV status and therefore may unknowingly be at risk of becoming infected with HIV or transmitting HIV to their partner(s).
Research shows that when people become aware of their HIV infection, most take measures to reduce their risk of transmitting HIV to others. Furthermore, studies suggest couples who test and learn their status together are more likely to adopt preventive measures than those who test alone.
Couples HIV testing and counselling allows individuals to learn of their own status, and the status of their partner, and make decisions to prevent transmission together. In this context, counsellors can tailor prevention messages based on the couple's test results.
A benefit of couples learning their test results together is that they can support each other, if one or both partners are HIV-positive, to access and adhere to ART for their own health and to prevent transmitting HIV to their partner or infant.
Also, the HIV-negative partner in a serodiscordant relationship may be able to protect themselves from HIV infection by taking antiretrovirals. This strategy is known as pre-exposure prophylaxis (PrEP).
Couples testing and counselling can help partners make informed decisions together with regards to reproductive health and family planning, including contraception and conception. Antiretroviral therapy or PrEP may be options to prevent HIV transmission when attempting to conceive.
Testing and counselling for couples, with support for disclosure, may help couples come to terms with their partner's HIV status in a way that strengthens their relationship and can prevent stigma and violence. A counsellor can play an important role in creating a safe environment that can help ease tension and diffuse blame.
Over the past decade, evidence has been accumulating that shows antiretroviral treatment can reduce the risk that a person living with HIV transmits the virus to others. Last year, an important randomized controlled study known as HPTN 052 found that when HIV-positive partners in heterosexual serodiscordant relationships started ART early (with a CD4 count between 350 and 500 CD4 cells), HIV transmission was reduced by 96%.
Based on this study, and others, the WHO made two recommendations on the use of antiretroviral therapy to prevent HIV transmission between serodiscordant couples:
Currently, the WHO treatment guidelines do not recommend that people start ART for their own health if they have a CD4 count greater than 350 CD4 cells. However, in contrast to the WHO treatment guidelines, guidelines in high income countries generally recommend people living with HIV start treatment when their CD4 count falls below 500 cells. These recommendations are based on observational studies, which suggest that earlier treatment may improve the health of people living with HIV. Recently the US Department of Health and Human Services changed its guidelines to recommend treatment for all HIV-positive people who are ready to start regardless of their CD4 count.
The WHO guidelines on couples HIV testing and counselling emphasize that counsellors must ensure that HIV-positive individuals who are offered earlier treatment fully understand the purpose of this option and make an informed choice to start treatment. A number of factors must be taken into consideration when making the decision to start treatment earlier, such as the potential for side effects, the commitment to lifelong adherence, and the possibility of drug resistance developing due to poor adherence.
Counsellors must also ensure that couples are aware of other options for preventing HIV transmission, such as the consistent and correct use of male or female condoms. The following key messages with regards to condoms and antiretroviral therapy for prevention are outlined in the guidelines:
The WHO guidelines acknowledge that there is a lack of evidence with regards to how much ART reduces the risk of HIV transmission among populations other than heterosexual couples, such as gay couples and people who use injection drugs. However, the guidelines state that an "international scientific consensus is emerging that ART significantly reduces the risk of sexual HIV transmission of HIV regardless of the population or setting."
In the past year several randomized controlled trials have found that HIV-negative individuals who take specific antiretroviral pills as pre-exposure prophylaxis are at reduced risk of HIV infection. The WHO is currently reviewing this evidence and plans to publish "rapid advice" on PrEP for heterosexual serodiscordant couples later this year. More detailed guidance will follow this advice.
Couples HIV testing and counselling provides an important opportunity to strengthen our HIV prevention efforts and should be offered in places in Canada where HIV testing is being done. Supporting linkages from HIV testing and counselling to appropriate treatment, care and support services will be important to fully realize the potential benefits of this couple-based intervention.
The Positive Side: "Treatment Benefits for All?"
TreatmentUpdate: "HPTN 052 -- The Trial That Changed Everything"
James Wilton is the project coordinator of the Biomedical Science of HIV Prevention Project at CATIE. James has an undergraduate degree in Microbiology and Immunology from the University of British Columbia.