Antiretroviral Therapy (ART) reduces the risk of HIV transmission within couples where one partner is HIV-positive and one HIV-negative by between 42% and 64%.
Photo Credits: Trevor Samson (L), webctor.com (R)
Why is ART as prevention important?
- Antiretroviral drugs reduce the risk of HIV transmission from mother-to-child and are used for post-exposure prevention after sexual or injection-based exposures. This suggests that treatment with ART could reduce the risk of transmission to a non-infected sexual partner.
Does ART as prevention work?
- ART reduces the risk of HIV transmission in HIV discordant couples. HIV Discordant couples by definition are stable sexual partners in which one member is infected with HIV and the other uninfected.
Equity: does ART as prevention work in the disadvantaged?
- This review found the intervention to be more effective in low- and middle-income countries than in high-income countries.
Intervention Delivery
- The RCT compared immediate ART to delayed ART (until CD4 falls below 250). The observational studies compared treatment with ART to treatment without ART.
Population and Setting
- This review included results from one RCT conducted in nine countries: Botswana, Brazil, India, Malawi, Kenya, South Africa, Thailand, United States, and Zimbabwe and included mostly heterosexual partners but 3% homosexual partners.
- The nine cohort studies were conducted in Italy, Brazil, Zambia, Rwanda, South Africa, Uganda, Spain, China, Botswana, Kenya, and Tanzania. Most of these studies included partners infected heterosexually.
- The HIV-positive case was male in some couples but female in others. Two studies included predominantly partners of heterosexual injection drug users.
Summary of Findings [SOF] Table: Antiretroviral therapy for HIV prevention in discordant couples
Patient or population: Couples in which one partner is HIV-positive and one is HIV-negative
Settings: Botswana, China, India, Italy, Malawi, Kenya, Rwanda, South Africa, Spain, Thailand, Uganda, US, Zambia, Zimbabwe
Intervention: ART
Comparison: Delayed treatment, No treatment with ART
Outcomes | Anticipated absolute effects per year | Rate ratio | No of Participants | Quality of the evidence | ||
Risk without ART (Control) | Risk with ART (95% CI) | |||||
Virologically linked HIV incidence1 (RCT) | 17 per 10002 | 16 fewer (from 12 to 17 fewer) |
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HIV incidence (observational studies) | 54 per 10003,4 | 23 fewer (from 3 to 35 fewer) | RR 0.58 (0.35 to 0.96) | 46,204 (9 studies) | moderate | |
HIV incidence (observational studies, sensitivity analysis) | 48 per 10003,4 | 31 fewer (from to 40 fewer) | RR 0.36 (0.17 to 0.75) | 46560 (7 studies) | moderate5 | |
Adverse events: in the RCT, 14% of the participants both the delayed and early treatment arms had severe adverse events such as infections, gastrointestinal disorders, metabolic and nutritional disorders and psychiatric and nervous system disorders. | ||||||
1. “Virologically linked” means that the newly infected partner has the same strain of HIV as their partner.
2. Few events and/or wide confidence interval.
3. Less than 5% of sample was imputed due to missing information in the denominator
4. Numerators and denominators taken from text where possible. Numbers were not used to calculate the relative effect estimates.
5. Two studies were removed due to differences in intervention or incomplete data.
Relevance of the review for disdvantaged populations
Antiretroviral Therapy (ART) reduces the risk of HIV transmission within couples where one partner is HIV-positive and one HIV-negative by between 42% and 64%.
This review found the intervention to be more effective in low- and middle-income countries than in high-income countries.
Findings | Interpretation |
Equity – Which of the PROGRESS groups examined |
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The included studies were conducted in both high-income (HIC) and low- and middle-income countries (LMIC). The participants in the studies were mostly heterosexual couples although the RCT and three cohort studies included homosexual partners. | ART is effective for prevention of HIV transmission in heterosexual partners and is most likely to be effective among homosexual partners. |
Equity Applicability |
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The studies conducted in LMIC found a greater benefit from ART than those in HIC which found a benefit, but it was not statistically significant. | These results came from the observational studies and only two of the nine observational studies were conducted in HIC countries. However, the results suggest that ART is effective for prevention and these results are likely applicable in both LMIC and HIC settings. |
The review did not report on whether there is a difference in effectiveness depending on which partner in heterosexual couples is receiving ART. In addition, the review did not on any other subgroup differences, such as those related to social capital, socio-economic status, or place of residence (urban/rural). | Future research should examine whether there is a difference in effectiveness of ART for prevention in male or female index partners as well as any differences in effectiveness for couples with varying socioeconomic status, social capital, or place of residence as these may effect access and adherence to ART. |
Cost-equity |
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The review did not report on the cost of ART for prevention. | Policy makers need to consider the additional costs of recommending ART for prevention. This would require a long-term commitment to treatment. In resource-limited areas, policy makers need to weight the cost of ART as prevention against the costs of treating HIV infection. In addition, if resources are limited, policy makers need to consider the costs of diverting resources from ART as treatment for HIV to HIV for prevention. |
The study did not report on how and when ART was provided to patients. | Policymakers will need to consider the feasibility of ART for prevention and determine how and when ART should be provided. In addition, the resources to purchase and sustain an ART supply as well as the human resources to prescribe, monitor, and counsel patients and their partners. |
Comments on this summary? Please contact Jennifer Petkovic.