Staying Healthy and Reducing Transmission
Sexual risk reduction for people living with HIV is important to stay healthy by reducing exposure to sexually transmitted infections that can accelerate HIV disease progression and by reducing exposure to drug resistant strains of the virus. It's also an important step to reduce transmission to new HIV-negative partners (Brown and DiClemente, 2011).
Risk Reduction is Necessary During the Acute Stage When HIV is Highly Transmissible
Acute HIV infection, lasting weeks or months, may account for a substantial proportion of HIV-1 transmission worldwide, though some have argued that acute infection is only responsible for a small percent of new infections (Williams et al., 2011b). Acute infection is a highly infectious stage occurring immediately following infection, yet before a rapid test can detect HIV infection, usually lasting between 7 to 21 days (Cohen et al., 2011b). "Viral burden is particularly high during this brief period, resulting in individuals being highly infectious" (Powers et al., 2008: 560). The efficiency of HIV transmission is directly proportional to the viral load in the transmitting individual (Quinn et al., 2000), i.e., the higher the viral load, the easier it is to transmit HIV. Yet it is difficult, if not impossible, "to quantify risks -- with an appropriate degree of accuracy -- for any specific individual in the 'real-world'" in terms of risks for HIV transmission (Gerberry and Blower, 2011: 1120).
Acute HIV infection usually progresses in the absence of treatment, into a state of chronic HIV infection that can remain relatively constant for years. While this period is associated with a much lower risk of transmission compared with that of acute HIV infection, because the period following acute HIV infection can last a median duration of eight years, the cumulative risk of transmission during these eight years can be substantial (Granich et al., 2009). There is no data to support how to reduce viral load by treatment of patients with acute infection (Cohen and Gay, 2010; Vinikoor et al., 2012) and best practice for the clinical management of acute HIV infection remains unknown (Bell et al., 2010; Hogan et al., 2012). Some have argued that, "in light of recent reports from the HPTN 052 study showing the benefits of early initiation of antiretroviral therapy in reducing sexual transmission rates for HIV infection, the case could be made for antiretroviral therapy as a public health intervention in persons with early HIV infection" (Tossonian and Conway, 2012:11).
Stigma Can Make Efforts to Reduce Transmission Difficult for Women
Non-judgmental, non-stigmatizing interventions to reduce HIV transmission to sexual partners are urgently needed (Collins et al., 2008). Interventions both within the health sector and outside the health sector, for example, those that transform norms, reduce violence against women, promote legal rights, etc, also need to be implemented in order to support safer sexual behavior once someone knows his/her positive serostatus. [See also Strengthening the Enabling Environment]
"I will never get a man here... if I am known to have HIV." --HIV-positive woman in Kenya (Awiti Ujiji et al., 2010)
Women who test HIV-positive report that their male partners often do not want to know that they are positive. One study describes the dilemma faced by some women: "He could not sleep with her if she knew she was positive. She (was)... torn by her dilemma: he refused condoms and she felt she could not insist without disclosure; yet she risked giving him the virus." Women "reflected upon the fact that men seemed unwilling to test but preferred to blame their female partners" (MacGregor and Mills, 2011: 4). Both women and men need to learn how to negotiate safe sex prior to disclosure, knowing when to disclose and how to disclose. Women in one study noted that once they disclosed, no man had stayed with them (MacGregor and Mills, 2011). In another study in Uganda, "the need to provide for children was a particularly strong motivation for women to avoid disclosure" (Allen et al., 2011: 539), as men abandoned or abused partners who disclosed or requested condom use. One cross sectional survey in Cameroon found that HIV-positive women who were not financially dependent on their male partners were much more likely to have used condoms (Loubiere et al., 2009), suggesting the importance of the enabling environment. [See Strengthening the Enabling Environment] Knowing a sexual partner is HIV-negative has been shown to be associated with increased condom use -- a study in Kenya with 3,013 adults found that ART-experienced adults who had HIV-seronegative partners were 17 times more likely to use a condom than ART nave adults who were unaware of their partner's serostatus (Benki-Nugent et al., 2011), with similar findings in the Dominican Republic (Sears et al., 2011).
Transmission can also occur in the attempt to become pregnant: "In the absence of artificial insemination technologies, effectively unavailable in most low- or low-to-middle income countries, conception requires unprotected sexual intercourse; this means risk of either HIV transmission (in serodiscordant couples) or HIV super-infection (in couples where both couples are positive)" (London et al., 2008: 14). [See also Safe Motherhood and Prevention of Vertical Transmission ] Super-infection is when a person gets infected with different strains of HIV, increasing the risk of drug resistance to ARVs. A study in Uganda found that polygamous relationships among HIV-positive partners results in multiple infections, i.e., super-infection (Ssemwanga et al., 2011). One study found that among 20,220 people in the study in Uganda in a general heterosexual population, rates of super-infection occurred at approximately the same rate as HIV incidence (Redd et al., 2012) and another study detected super-infection among Kenyan women (Ronen et al., 2012).
HIV-related stigma contributes to repercussions on relationship stability, affecting the couples' sexual relationship. Some serodiscordant couples identify fear of transmission as a primary concern in their relationships or fear the impact that disclosure will have on the HIV-negative partner (Talley and Bettencourt, 2010; Chen et al., 2011; Kelley et al., 2011). A study in South Africa found that among 413 HIV-positive men and 641 HIV-positive women, stigma and discrimination was associated with non-disclosure and that non-disclosure was associated with HIV transmission risk behaviors (Simbayi et al., 2007).
The Relationship Between HIV and Other STIs is Complicated
Acquiring STIs can accelerate HIV disease progression (White et al., 2006 cited in Brown and DiClemente, 2011) and increase the risks of HIV transmission (Ward and Ronn, 2010 cited in Brown and DiClemente, 2011). According to Brown et al., "infectiousness is high in HIV-infected individuals with a concurrent STI" (Brown et al., 2011a: 441). STIs in those who are HIV-positive may be associated with a faster progression to death. A study between 2001 and 2009 with 303 HIV-positive women with 1,408 person-years in Uganda and Zimbabwe found that STI symptoms were associated with faster disease progression (Morrison et al., 2011). Women who are HIV-positive also have increased risks for certain STIs, such as genital ulcer disease, even after initiation of antiretroviral therapy; one study found an increased risk of Trichomonas vaginalis (Mavedzenge et al., 2010b). A study in Taiwan of 123 HIV-positive patients found repeated infection with STIs since HIV diagnosis (Lee et al., 2010).
Conversely, HIV treatment can also benefit certain STI outcomes. A study found that HIV-positive patients on ARVs with syphilis are less likely to have neurosyphilis and respond better to neurosyphilis treatment (Marra et al., 2012). Among entirely or predominantly ART nave adults, a systemic review found that treating STIs reduced HIV viral load (Modjarrad and Vermund, 2010). Questions have been raised about whether herpes simplex-2 infection, in particular, enables HIV transmission, though recent observational data found no association between HIV transmission with HSV-2. Clinical trials "found no effect of HSV-2 suppression on HIV acquisition and HIV transmission in HIV discordant couples. The biological basis of the relationship between HSV-2 infection and risk of HIV acquisition/transmission requires further study" (Biraro et al., 2012: 1).
Randomized evaluations of different behavioral intervention models, including clinician-initiated communication are needed (Bunnell et al., 2006b). "When discussions of ongoing STD-related risk behavior do occur, they are infrequent and often initiated at the patients request. At best, the lack of these discussions in HIV-related care settings is unfortunate; at worst, it indirectly contributes to escalating rates of STDs among HIV-infected persons and of new HIV acquisition among others at risk" (Hall and Marrazzo, 2007: 518.)
Treatment Can be a Successful Prevention Strategy to Reduce Transmission
The HPTN 052 study has shown that early initiation of antiretroviral therapy (when CD4 counts were between 350 and 550 -- before many would normally be eligible under current initiation thresholds for treatment in most countries) for the seropositive partner in a discordant relationship resulted in a 96% relative risk reduction of HIV transmission to the seronegative sexual partner (Cohen et al., 2011a). The results of this study have led many to recommend the use of treatment as a prevention strategy and WHO has released normative guidance on early treatment for serodiscordant couples (WHO, 2012g).
While this study shows the benefit of treatment for reduction of transmission to the HIV uninfected partner, it is important to keep this study in context. Condoms as well as treatment were used to prevent transmission, with self-reported 100% condom use correlated with prevention of transmission. There are a number of hurdles in successfully utilizing this treatment as prevention approach. For example, getting all HIV-positive people to know their serostatus before they are symptomatic and while their CD4 counts are above 350 in order to access treatment will be challenging and unlikely to result in universal coverage in the near future (Over, 2011). Also of significance in the study by Cohen et al. is that in 28% of the cases HIV transmission occurred from another partner rather than from the HIV-positive partner on treatment (Cohen et al., 2011a), demonstrating that monogamy cannot be assumed in serodiscordant couples (Ambrosioni et al., 2011; Smith et al., 2011; Abdool Karim and Abdool Karim, 2011). Early treatment will not stop transmission from those who are acutely infected but cannot know their serostatus with regular HIV tests (Cohen, 2011b).
"Increasingly, there has been recognition of the need for services to work with couples, rather than just with the individual partners" (Spino et al., 2010: 4). "Although early ART for serodiscordant couples (where one partner is infected) may be feasible in many settings, offering immediate treatment for prevention to all who test HIV-positive is challenging in settings where barely 50% of those medically eligible (based on decline in CD4 cell count [under 350]) are receiving ART" (Shattock et al., 2011: 42). At the same time, it is unclear whether reducing HIV acquisition between sexual partners in a serodiscordant couple will have a major impact on HIV incidence and prevalence (Gray et al., 2011).
"Me, I try to tell the man that, 'In this house we have been found with this problem. We should accept it. I should not point a finger at you. You, too, should not point a finger at me. Just buy your protection.' And so, little by little what he does now is different from what he did in the past." --HIV-positive woman, Malawi (Mkandawire-Valhmu and Stevens, 2010: 691)A recent assessment in Uganda found that voluntary counseling and testing targeting discordant couples is unlikely to have a substantial impact on reducing HIV acquisition among the larger population. The study found that HIV infections before the availability of antiretroviral therapy was 82 out of 9,434 people or 18.3% and after the availability of antiretroviral therapy was 131 out of 13,082 people or 13.7%. Most new infections occurred among people not currently married or among married individuals with a partner of unknown serostatus. In addition, 23.2% of infections pre-ART and 26% post-ART occurred among initially concordant HIV-negative couples in whom the new infection must have been introduced from an extramarital relationship (Gray et al., 2011). "Antiretroviral therapy is by no means perfect and is not the ultimate answer to controlling and ending the HIV epidemic. Adverse events, emergence of drug-resistant viral strains, maintenance of adherence, sustainability and cost are just some of the concerns. However, this is precisely the wrong time to limit access to antiretroviral therapy in resource-limited settings, since we have the tools in hand to maintain or restore health in infected persons and to reduce transmission to their sexual partners" (Hammer, 2011: 562).
"If earlier treatment is expanded... many more people will need to be on treatment in the short term" (IOM, 2011: 3). Reliable point of care for CD4 counts which could be used without laboratory facilities are being developed (Moon et al., 2011; Mtapuri-Zinyowera et al., 2010; Barnabas et al., 2012). Once these point of care CD4 analyzers are reliable and rolled out, testing outside of health care facilities can be more efficiently linked to knowledge of when a particular patient can and should initiate antiretroviral therapy. "An essential question is how a country's health service could maintain antiretroviral therapy in legions of healthy patients with high CD4 cell counts mainly for prevention benefits to partners, when it is not able to initiate and maintain high levels of retention of those with low CD4 counts who need ART for survival" (Padian et al., 2011b: 275).
While the use of HIV treatment as prevention is emerging as an exciting component of scaled up AIDS programs, further research and clarification is needed. A number of mathematical models have demonstrated the potential benefits of treatment as prevention (Mahy et al., 2010b). "The reliability of projections developed from mathematical models is limited by the accuracy of the assumptions on which a model is built and by the realities of implementation. Additional areas of uncertainty range from questions regarding the accuracy of mathematical models used in recent publications to questions regarding the acceptability and impact of massive scale up of HIV testing, and of long-term treatment in people where HIV treatment may not yet [be] medically indicated but is being prescribed to prevent HIV transmission. Many of these questions will be addressed by studies planned or underway" (IAS, 2010: 6).
Further discussion of the use of treatment as a prevention strategy can be found inTreatment as Prevention.
Treatment Alone Will be Insufficient in Reducing Transmission
Though ARV treatment can reduce transmission through reduced viral load (Attia et al., 2009; Vernazza et al., 2008), condom use is still necessary to increase protection for both HIV-positive and HIV-negative sexual partners. "Programs need to link treatment with prevention" (Holmes et al., 2010b: 177). "Given the dramatic effect of ART on viral load, it is reasonable to consider using treatment of individuals infected with HIV as a means of preventing HIV transmission" (Dieffenbach and Fauci, 2009: 2380) and recent results "support the use of antiretroviral treatment as a part of a public health strategy to reduce the spread of HIV-1 infection" (Cohen et al., 2011a: 501). However, "the burden of adding antiretroviral-based prevention to already strained health systems remains to be determined" (Padian et al., 2011b: 271). [See also Prevention for Women]
Treatment cannot replace the use of condoms. The proper use of condoms remains a reliable means of enabling everyone, without knowing the serologic status of their partners, to keep control on protecting themselves and others during sexual intercourse. UNAIDS also argues that reducing transmission is a "shared responsibility," so that everyone shares the responsibility to avoid infection (GNP+ and UNAIDS, 2011). "Treatment should be thought of as a tool providing regular condom users valuable extra safety. Moreover, condoms remain the only way to protect oneself against other STIs" (Bourdillon et al., 2008: 11). Some studies have shown that those on treatment are more likely to use condoms (Kennedy et al., 2010b) and other measures to prevent transmission and other studies, mostly from resource-rich settings (Tun et al., 2004 cited in Cohen and Gay, 2010) have shown the opposite, but most studies have not adjusted for baseline sexual behavior prior to ART (Cohen and Gay, 2010).
Some researchers have expressed concerns that risk behaviors may increase "due to the feeling of safety that ART provides" (Shafer et al., 2011: 671) and increasing HIV prevention efforts both for those who are HIV-negative and for those who are HIV-positive is necessary (Shafer et al., 2011). A study in the United States found that those who believed that having an undetectable viral load reduces transmission risks could be at risk of transmitting HIV due to STI co-infections (Kalichman et al., 2010). Individuals need counseling on the relationship between their CD4 count and the risk of transmission both to sexual partners and in pregnancy in a simple, easy to understand format (Awiti Ujiji et al., 2011). [See also Meeting the Sexual and Reproductive Health Needs of Women Living With HIV and Safe Motherhood and Prevention of Vertical Transmission ] Further, the risk factors for serosorting (condomless sex between two HIV-positive people who are on effective antiretroviral therapy and confirmed low viral loads), warrants more research (Anstee et al., 2011).
Some of the challenges of treatment prevention include missing acute infections, long-term adherence, the possibilities of drug resistance, and the concerns that condom use and other preventive measures would decrease (Shelton, 2011a). Given the unknowns and the inadequate availability of medications, treatment alone is insufficient in reducing and preventing HIV transmission. In addition to antiretroviral therapy "all treatment programs should provide patients with routine risk-reduction counseling, access to condoms and other prevention tools, and other prevention services in their clinical settings" (Global HIV Prevention Working Group, 2008: 23). For additional prevention strategies see Prevention for Women; Prevention for Key Affected Populations and Prevention for Young People.