The cost and cost-effectiveness of gender-responsive interventions for HIV: a systematic review

Introduction Harmful gender norms and inequalities, including gender-based violence, are important structural barriers to effective HIV programming. We assess current evidence on what forms of gender-responsive intervention may enhance the effectiveness of basic HIV programmes and be cost-effective. Methods Effective intervention models were identified from an existing evidence review (“what works for women”). Based on this, we conducted a systematic review of published and grey literature on the costs and cost-effectiveness of each intervention identified. Where possible, we compared incremental costs and effects. Results Our effectiveness search identified 36 publications, reporting on the effectiveness of 22 HIV interventions with a gender focus. Of these, 11 types of interventions had a corresponding/comparable costing or cost-effectiveness study. The findings suggest that couple counselling for the prevention of vertical transmission; gender empowerment, community mobilization, and female condom promotion for female sex workers; expanded female condom distribution for the general population; and post-exposure HIV prophylaxis for rape survivors are cost-effective HIV interventions. Cash transfers for schoolgirls and school support for orphan girls may also be cost-effective in generalized epidemic settings. Conclusions There has been limited research to assess the cost-effectiveness of interventions that seek to address women's needs and transform harmful gender norms. Our review identified several promising, cost-effective interventions that merit consideration as critical enablers in HIV investment approaches, as well as highlight that broader gender and development interventions can have positive HIV impacts. By no means an exhaustive package, these represent a first set of interventions to be included in the investment framework.


Introduction
Three decades into the epidemic, HIV incidence remains persistently high in some regions, and HIV/AIDS is still a leading global cause of morbidity and mortality [1]. Gender inequality is an important driver of the epidemic, particularly in Sub-Saharan Africa, where women and girls represent 58% of people living with HIV [2Á4]. Rigid gender roles, along with gender disparities in education and employment, severely limit women's ability to negotiate sex and condom use [5]. In addition, power inequalities between women and men, and the fear or experience of violence may increase HIV vulnerability and limit women's access to HIV services or adherence to HIV prevention or treatment technologies [6Á11]. This makes HIV prevention especially difficult for women and girls.
In the context of limited resources and the political commitment to the HIV response, UNAIDS and partners have proposed an investment approach to ensure that resources are invested in the most cost-effective interventions, including for populations most at risk [12]. This ''investment framework'' advocates for the prioritization of six ''basic programmes'' that directly reduce HIV transmission, morbidity and mortality. The framework also identifies the importance of complementary ''critical enablers'' Á activities that are necessary to support the effectiveness and efficiency of basic programmes, and need to be funded as part of the HIV response. The potential value of synergistic investments in other health and development sectors that may have HIV-related impacts (''development synergies'') Á and could partly be supported through the HIV response Á is also stressed [13].
The investment framework has played an important role in framing budget estimates and national-level planning and grant negotiations [14]. Estimates of the global cost of implementing the investment framework were produced in 2011, with the costs of critical enablers being produced by estimating the costs of community mobilization, and then adding a 10% mark-up on the costs of basic programmes, as a rough proxy for the potential costs of other enabling activities [12]. Overall, it has been estimated that critical enablers and development synergies could be allocated over 40% of the HIV resource base, but this is far from the reality at country level [15,16].
Although recognized as important, there has been a lack of clarity regarding how or what gender-responsive interventions should be included in HIV investment approaches [17]. Gender equality and gender-based violence (GBV) programmes were initially classified as development synergies, but are increasingly recognized as also integral to an effective response [13,18]. Given the particular challenges that women and girls face in accessing and benefiting from basic HIV programmes, it is important to assess whether some programme components function as critical enablers and should be more explicitly included in national HIV responses and in the investment framework [19,20].
All programmatic interventions can be classified along a ''gender continuum'' according to the level of change they seek to achieve [21,22]. We consider an intervention to be ''gender-responsive'' if it takes into account and addresses the different needs of women/girls and men/boys in its design, or explicitly aims to redress existing inequalities between the sexes. A number of previous reviews have looked at the effectiveness of gender components in selected HIV programme areas, but none have considered their costeffectiveness [8Á10,23Á29]. To address this gap, this paper systematically reviews evidence on the costs and costeffectiveness of effective gender-responsive HIV interventions. In addition, where this has not been done, it seeks to explore the incremental cost and effects of gender-responsive programme components.

Methods
Our approach consisted of three main steps. We first synthesized existing evidence on effective gender-responsive HIV interventions from low-and middle-income countries, drawing on the findings from an existing review on what HIV interventions work for women [30]. For the effective interventions identified, we then conducted a systematic review of their costs and cost-effectiveness. Finally, where feasible, comparisons were made between costs and effects to obtain measures of the potential incremental impacts attributable to the inclusion of gender-responsive investments.

Effectiveness synthesis
Existing evidence on the effectiveness of gender-responsive HIV interventions was extracted from an extensive review conducted with support from the US President's Emergency Plan for AIDS Relief's Gender Technical Working Group and the Open Society Foundations [30]. We used this database (www.whatworksforwomen.org) to identify effective interventions. For each intervention identified, we reviewed the primary source article, and retained studies that met the following inclusion criteria:

1) Effectiveness evidence rated as I to III on an adjusted
Grey scale (i.e. Grey scale I for a systematic review, Grey scale II for a randomized controlled trial, Grey scale IIIa for a study without randomization but including a nonequivalent control group, and Grey scale IIIb for a study without randomization or a control group) [30,31]. 2) Contained data from a low-or middle-income country.
3) Presented quantitative intervention impact data on either reported HIV-related behaviours or biologically confirmed outcomes (including studies that used reported behavioural data to model impacts on HIV transmission).
When compiling the evidence on effectiveness, we chose to group the interventions identified into three types. The first are gender-responsive activities that can be added to basic HIV programmes to enhance their effectiveness and efficiency by addressing gender-related barriers to behaviour change, service uptake and retention (HIV'). The second comprises HIV-specific interventions that could be added onto genderresponsive development programmes, to achieve a synergistic HIV effect (Gender'). The last type (Gender) consists of gender-responsive development interventions that do not explicitly include programmatic HIV components, but may nevertheless have secondary HIV benefits because of their impact on gender inequalities and/or violence.

Cost and cost-effectiveness search
To identify all published costing and economic evaluation studies of gender-responsive HIV interventions, we searched PubMed, EconLit, Eldis and HIV, and gender websites, following PRISMA guidance [32]. The terms searched thematically covered 1) HIV/AIDS, 2) gender, 3) intervention, and 4) economic/impact evaluation (see Supplementary appendix for more details).
Articles identified were included if they had been published in English, French or Spanish between 1 January 1990 and 30 June 2014; presented cost or economic evaluation data; and assessed gender-responsive interventions. Additional bibliography searches from review articles were conducted and recommendations from the UNAIDS expert reference group considered (An expert reference group was established by UNAIDS to provide technical guidance to the study, including representatives from other UN organizations, donor agencies, civil society and academia.). Additional articles analyzing intervention effectiveness that were identified through this search were included under the effectiveness category if they met the inclusion criteria mentioned above.
The only exception to the review was data on the integration of sexual and reproductive health and HIV services. Integration is a gender-responsive intervention, as it restructures services to better meet women's needs. However, as a recent systematic review has extracted this cost-effectiveness data [33], we used its findings, but did not repeat the review as part of this project.
After the first title-based screening, citations were downloaded into reference management software (Endnote X3) for a second round of title/abstract screening, conducted by another researcher. Full texts were then read to ensure correct inclusion. Any uncertainty was resolved through discussion among at least two authors.

Data extraction
A data extraction spreadsheet was developed, capturing intervention and study characteristics. Outcomes related to HIV/STI (sexually transmitted infection) incidence or prevalence, disability or quality-adjusted life years (DALYs/QALYs), proxies of unprotected sex (marriage rates, pregnancies), sexual behaviour, HIV service uptake and risk factors (e.g. experiencing violence) were extracted. For the costing studies, we also extracted detailed information on methods and cost estimates. Costs were adjusted to 2011 United States' Dollars (US$).

Quality assessment and data synthesis
The quality of the costing and economic evaluation studies was assessed using an adapted version of the British Medical Journal's checklist for economic evaluations [34] (see Supplementary appendix for more details). Two reviewers scored study quality independently and discrepancies were resolved through discussion.
Given the diversity of the interventions, outcomes and costing methodologies, we adopted a narrative approach to data synthesis [35].

Analyzing the return on investment
Interventions with a cost per DALY averted or QALY gained below the country's per capita gross domestic product (GDP) [36] were considered cost-effective, as per the lower threshold of WHO [37]. Where a cost per HIV infection averted was estimated, we translated this into a cost per DALY averted for antiretroviral therapy (ART) and no-ART scenarios, using standard DALY formulae and country-specific life expectancy at birth from WHO, as described elsewhere [38,39]. For studies that did not estimate cost-effectiveness ratios (CERs) that could be compared to the WHO threshold, costs were analyzed alongside effects from the same study and/or studies from the same country.
Where the intervention was clearly an incremental investment on a basic HIV programme or an HIV component of a gender-responsive health or development programme, the cost markup was estimated using internally consistent data from the same study, where possible. Otherwise, approximate cost markups were estimated by comparing the unit cost of the gender-responsive component to the countryspecific cost used in the investment framework for the specific basic HIV programme or development synergy [12].

Evidence of effectiveness
The effectiveness search identified 36 publications describing 22 gender-responsive interventions found to be effective for HIV ( Figure 1). Most of the studies [25] evaluated interventions in countries with generalized epidemics. Interventions for key populations and those focussed on young men came primarily from concentrated epidemics. Thirteen interventions had at least one randomized controlled trial demonstrating HIV-related effects, whereas nine interventions were assessed without randomization, without a control group, or through modelling. In addition, only nine intervention models had been evaluated in multiple trials/studies. Only three studies assessed impact on HIV or other biological outcomes (Herpes simplex virus type 2 (HSV-2) and pregnancy) [40Á42], with the majority considering proximal determinants of HIV risk (namely reported behaviours and experiences).
Gender-responsive activities for programmes to prevent vertical transmission included promoting male involvement through couple counselling [43Á46] and training women living with HIV peer support groups [47Á49], which enhanced the uptake and adherence to these prevention services, thereby averting more infant infections [50].
In terms of key population programmes, effective genderresponsive components were identified for female sex workers (FSWs) and people who inject drugs (PWID). The former included community mobilization to prevent violence and promote gender empowerment through collectivization and stakeholder engagement [51Á53]; educational sessions [54,55]; female condom promotion [56,57]; and micro-enterprise services [58,59]. An enhanced gender-responsive service package for FSWs with reported substance abuse, including womanfocussed personalized risk assessments and risk-reduction strategies, increased reported condom use and reduced client and intimate partner violence (IPV) [60,61]. Couple-based educational sessions for PWID were an effective genderresponsive programme component, increasing reported condom use and safe injections [62].
In terms of condom promotion, modelling suggests that expanded female condom promotion and distribution to increase availability could increase consistent condom use among the general population [63]. Another study of a gender-responsive condom negotiation training intervention for married women in Zimbabwe also found improved ability to negotiate increased condom use [64] (Table 1).
Traditional HIV behaviour change interventions were proven to be enhanced by more gender-responsive approaches, some of which worked with women only, men only or both. Two studies assessed women-focussed HIV risk reduction interventions in South Africa and India that were based on the theory of gender and power, and aimed to build skills in relationship communication and control. Both interventions reduced the rate of reported unprotected sex [65,66], but no effect was found on STI incidence [66]. The former is particularly promising given that the ''Raising HIV Awareness in Non-HIV-infected Indian Wives'' intervention in India specifically targeted vulnerable women whose husbands engaged in excessive drinking or lifetime physical or sexual spousal violence perpetration [65].
There was evidence of the effectiveness of genderresponsive approaches that promoted a participatory process of critical reflection and debate about gender norms and expectations in relationships. A randomized controlled trial of a participatory gender training with young women and men in South Africa (''stepping stones'') showed a significant incremental impact on HSV-2 incidence, male reported problem-drinking, male soliciting transactional sex and male reported perpetration of violence, although no impact on female reported experience of violence was found [40]. Quasiexperimental evaluations of group interventions with young men, from Brazil, South Africa and India, also found increases in reported condom use and HIV testing, as well as reductions in reported STI symptoms and the reported perpetration of IPV [67Á69].
In addition to approaches targeting enrolled individuals, a community mobilization intervention in Uganda (''SASA!'') seeking to promote community-level change in social norms to prevent violence against women and reduce HIV risk through a community diffusion approach delivered by community activists, led to a significant reduction in sexual concurrency reported by men in non-polygamous relationships and social acceptance of IPV by women [70].
There was also evidence that a multimedia ''edutainment'' model that integrated the prevention of GBV and HIV messages into a popular soap opera, both increased reported condom use and HIV testing, as well as reduced the acceptance of violence [71,72].
In terms of broader development programmes, a cluster randomized controlled trial (the IMAGE intervention) showed that the addition of participatory gender/HIV training onto an existing microfinance scheme for women in rural South Africa had a significant impact on levels of physical and/or sexual partner violence over two years, and also increased HIV testing and reduced unprotected sex among younger beneficiaries [73,74]. There was also evidence from Haiti suggesting that women's engagement in microfinance alone increased reported condom use and reduced reported numbers of sexual partners [75].
Three effective education-related development programmes were rigorously evaluated in randomized trials. A one-off school-based information session on relative HIV risk profiles by age and sex in Kenya (''sugar daddy talks'') significantly reduced teenage pregnancies [41]. Cash transfers or material support to schoolgirls had significant impacts, including reduced prevalent HIV and HSV-2 [42], reduced marriage rates [76] and delayed sexual debut [77].
Another potentially synergistic intervention for GBV prevention among female apprentices and hawkers in Nigeria suggested the potential to reduce violence in the context of HIV through stakeholder mobilization [78]. Finally, mathematical  Cohort study with a control group, comparing HIVpositive pregnant women whose partners were invited to come to the clinic for VCT (1), those whose partners came for VCT (2) and those who were counselled as a couple (3)           modelling predicted that adding post-exposure prophylaxis (PEP) for rape victims to GBV programming is an effective adjunct for preventing HIV transmission [79,80].

Evidence of cost-effectiveness
Our cost and cost-effectiveness search identified 14 publications, including 1 in submission [53] ( Table 2). Eleven were cost-effectiveness/costÁutility analyses and three were costing studies [81,82]. Of the 22 effective gender-responsive interventions identified, 11 had a corresponding/comparable costing or economic evaluation (Figure 2). Most only had one costing study, except PEP [80,81,83] and material support to schoolgirls [84,85]. Twelve studies contained data from generalized epidemic settings. The studies were of mixed quality, as described in more detail in the Supplementary appendix. Nonetheless, all but two [56,63] contained empirical cost data and half reported economic costs corresponding to the opportunity cost of the investment. Eight studies also provided a cost breakdown of total and/or unit costs. All studies estimated costs from a provider perspective, whereas one also considered societal costs [85]. This could hide considerable patient/participant/ community costs, whereby seemingly low-cost interventions may in fact have substantial costs for women and communities. Another important weakness of the cost data is that most estimates are from single sites and small-scale pilots, making it difficult to generalize them at scale.
Seven studies provided CERs in terms of costs per HIV infection averted, HIV DALY averted or HIV QALY gained [42,50,53,56,63,80,84]. This evidence suggests that couple counselling for the prevention of vertical transmission (US$17 per DALY averted); gender empowerment community mobilization for FSWs (US$13Á19 per DALY averted); female condom promotion for FSWs (US$32Á56 per DALY averted); expanded female condom distribution (US$24Á1499 per DALY averted); and PEP for rape survivors (US$2120Á2729 per DALY averted) are cost-effective HIV interventions, with CERs well below the respective countries' GDP per capita (WHO's threshold). By including orphan quality of life as an HIV outcome and various cost scenarios, we find that school support for orphan girls (US$6 per QALY gained) and cash transfers for schoolgirls (US$212Á912 per DALY averted) could also be cost-effective in generalized epidemics.
In the absence of relevant CERs in some studies, Table 3 summarizes the estimated additional investment required and the potential additional effect for each gender-responsive intervention with a corresponding basic HIV programme or development programme considered relevant to HIV responses. For example, although couple counselling may cost an additional 7% on standard screening in programmes to prevent vertical transmission, modelling suggests that the changes in uptake combine to avert 3.4% more infant infections [50]. This does not factor in the potential benefits to the parents from knowing their HIV-status and disclosure between couples.
Overall, these examples suggest that investment in strengthening the gendered components of projects Á though adding costs over and above basic programme costs Á could generate significant additional HIV benefits. Some may even be cost-saving, especially if averted treatment costs are considered. Such interventions include gender-responsive community mobilization for FSWs, female condom promotion for FSWs and PEP for rape survivors. It also appears that although female condom promotion (including for FSWs) and PEP may be highly cost-effective, they may be considerably under-budgeted in global resource needs estimates.
Unfortunately there was insufficient data to determine whether the remaining gender-responsive interventions, though effective, are good value for money. For example, although the unit costs of interventions working with young men to transform gender norms seem reasonable (US$106Á 158 per participant in Brazil), it was not possible to assess their HIV-related incremental effects or cost-effectiveness.

Discussion
This is the first study to systematically review the costs and cost-effectiveness of gender-responsive interventions for HIV. We identified a range of interventions with demonstrated impacts either on HIV or its proximate determinants. Most appear to function as the investment framework's critical enablers of basic HIV programmes, although several examples of development synergy type interventions were also identified ( Figure 2). The strategies identified include transformative interventions that influence the dynamics and balance of power within relationships; collectivization and peer support empowerment strategies; women-focussed interventions providing education, skills training and the development of self-efficacy; integrated gender and HIV behaviour change through multimedia, community mobilization or trainings that include men and boys; and economic support to poor women, FSWs and schoolgirls. However, many of these interventions had no economic analyses, making it difficult to assess their cost-effectiveness.
Where cost data were available, among the interventions found to be cost-effective, enrolling couples in programmes to prevent vertical transmission seems to help reduce the inefficiencies associated with high loss to follow-up along the service cascade [86,87]. Because counselling and testing is an entry point into ART, the only incremental cost would be that of generating male demand for counselling and testing in antenatal clinics [88]. The involvement of male partners is likely to be more cost-effective in high prevalence settings with higher uptake of couple counselling [50]. However, there may also be real risks of aggressively promoting such an approach, if it becomes a barrier to service access for single women, for example, or puts women in violent relationships at further risk [89]. For this reason, it will be important to assess whether such initiatives have unforeseen negative consequences that undermine their utility, and consider whether additional programmatic elements, to potentially mitigate this risk, may be needed.
Similarly, to be a more attractive investment, female condom promotion may require intensified demand creation through woman-focussed, transformative programmes and/or subsidised distribution. Although it is already considered a basic HIV programme and modelled studies found that it was cost-effective [56,63], it is currently not included in the investment framework for most countries with generalized          [50] 3.4% more infant HIV-1 infections averted [43] 3.4 times more likely to return for follow-up visits and administer nevirapine for delivery [43] 5 times more likely to adopt recommended infant feeding practices [ [12] Á possibly because of low demand coupled with high commodity costs. The cost of additional demand creation activities and their effectiveness at creating new demand among vulnerable women (rather than substituting demand for male condoms) will greatly influence the intervention's value-for-money [56,57]. Not surprisingly, concentrating on women at greatest HIV risk appears to be particularly costeffective [56]. Evidence from India suggests that gender-responsive community mobilization activities aiming to promote collectivization are highly cost-effective critical enablers to basic FSW programmes [53]. Additional research is needed to assess whether this model can be adapted and implemented cost-effectively in generalized epidemic settings.
Evidence from South Africa suggests that PEP for rape survivors is cost-effective [80] and an indisputable intervention to prioritize from a human rights perspective. Its costeffectiveness will depend on the underlying HIV prevalence among survivors and perpetrators, its early administration and adherence/completion rates [82].
The evidence from the IMAGE study of the impact of combined economic empowerment and gender/HIV training illustrates the potential to add HIV-specific components onto livelihood programmes for women, leveraging the development synergy, at low incremental cost.
Certain GBV prevention interventions could function as both critical enablers as well as development synergies. For example, gender-transformative activities focussing on young men could either be classified as critical enablers, where the gender norms component is integrated in standard group HIV behaviour change programmes; or as development synergies, where an HIV component is added to a broader gender transformation programme. This would have implications for their cost-effectiveness, as it would determine what such additional investments are incremental to. Similarly, mass media campaigns are already considered critical enablers of HIV behaviour change; hence, the more explicit inclusion of GBV prevention messaging could be considered a gender-responsive critical enabler. However, where such a multimedia campaign exists with a focus on GBV and gender transformation, this again represents an opportunity to leverage related development resources.
There is evidence that other gender-responsive development programmes can also influence HIV-related outcomes through structural pathways and still be cost-effective for HIV. The provision of cash transfers to keep girls in school [42,90], for example, could be cost-effective for HIV under certain conditions. Although such interventions could also be considered development synergies, they currently are not costed in the investment framework. This suggests that the scope of development synergies should be broadened, to consider potential investment options that are likely to achieve both HIV and non-HIV outcomes, and merit cofinancing, instead of focussing primarily on HIV-specific activities [91].
Although we did not review evidence on the impact and costs of the integration of sexual and reproductive health and HIV services, this area does merit consideration as a genderresponsive enabling approach, as it restructures services to Cost-effectiveness ratio GBV Integrated HIV post-exposure prophylaxis in post-rape services 2.2 times higher unit cost than GBV unit cost [80] in the investment framework (for South Africa) 0.6Á59.4% reduction in the number of HIV cases estimated as potentially resulting from rape [80] 3.13 times more likely for victims to complete the 28-day course of PEP drugs [82] US$2120Á2729 per DALY averted Highly cost-effective Education One-off session for girls on HIV prevalence among older men 6.3Á15% additional cost per pupil [41], compared to the investment framework unit cost for AIDS education in schools (global range) 28% decrease in the incidence of childbearing [41] Not available a Risk ratios calculated from Pulerwitz et al.  2005), based on 271/437 (38%) respondents exposed to three Soul City media types reporting always using condoms, compared to 22/373 (6%) not exposed to any Soul City media; and 95/592 (16%) respondents exposed to one Soul City media type reporting always using condoms, compared to the same control. GBV0Gender-based violence; FSW 0female sex worker.
better meet women's needs. A systematic review reported consistent and multiple HIV-related benefits from a range of integration models, including reduced HIV incidence [92]. Another review found that integrated programmatic approaches could lead to efficiency gains through economies of scale and scope, and be cost-effective or cost-saving, especially where HIV counselling and testing was integrated into family planning or family planning was integrated in services to prevent vertical transmission [33]. It is worth noting that the review did not identify any (cost-) effectiveness studies of gender-responsive components linked to ART, male circumcision or programmes for men who have sex with men and their female partners. Yet, gender inequalities in these areas underscore the need to ensure their gender-responsive delivery, particularly given the important share of HIV budgets that they claim with about 50% of HIV spending going to treatment and care across low-and middle-income countries [93,94].
This review has several limitations. Fundamentally, there is limited evidence on the costs and cost-effectiveness of gender-responsive interventions; and even fewer analyses of how gender-specific components may serve to increase the impact of basic programmes, or the potential impacts of HIV-relevant components in gender-specific development programmes. These are important areas for further investigation. We have included effectiveness studies even where cost/cost-effectiveness data was lacking in an attempt to highlight these gaps and recommend them as key opportunities for additional economic research.
We decided to include self-reported behavioural outcomes when considering intervention effectiveness, despite the known challenges of these indicators as proxies of behaviour change and programme effectiveness. The lack of availability of intervention evaluations with biological outcomes is not unique to this field, and the resulting conclusions need to be interpreted with caution. However, we felt that it was preferable to include such evidence as a starting point for programming, rather than have a potentially overly narrow focus of intervention evidence.
Although we were interested in incremental investments over and above basic programmes, not all retained studies actually measured this incremental cost/effect. For example, the GBV and HIV messaging in the Soul City multimedia campaign were fully integrated and it was not possible to isolate the GBV component's effect [72]. In such cases, we have been cautious with our conclusions and reflected this uncertainty.
Another important limitation is the extent to which single or a small number of studies per intervention have external validity. Moreover, the quality of the cost and effectiveness data was mixed, with particularly little consistency in outcomes measured and costing methods. This hampered any interpretation of the cost-effectiveness of gender-responsive training sessions with young men, for example.
Publication bias could also imply that we are overestimating effectiveness and by only considering interventions with quantifiable evidence of effect, we may have excluded important qualitative evidence, as well as complex interventions that are not amenable to experimental designs [95Á98].
Other promising interventions were excluded, because they did not include an explicit HIV focus [99Á101].

Conclusions
Despite the critical role of gender inequality and GBV in fuelling the HIV epidemic and impeding service effectiveness [7,11], there is a paucity of evidence on the (cost-) effectiveness of specific programme components to address women's needs and transform harmful gender norms for HIV impact. Where available, evidence suggests that genderresponsive interventions, including GBV prevention, can function as cost-effective critical enablers by addressing harmful gender norms and thus improving HIV service uptake, adherence and behaviour change. Indeed, our review identified a number of promising cost-effective gender-responsive interventions that merit consideration as critical enablers in the investment framework, as well as others that may be better placed as development synergies.
Given the many data gaps, these interventions are by no means an exhaustive package, but rather the first set of promising interventions in a neglected field. Countries may want to consider these interventions for gender-responsive HIV programming. Indeed, the absence of cost-effectiveness data should not be interpreted as evidence that these investments are not good value-for-HIV-money. More research is needed to establish the return on these investments, in terms of increased utilization of and adherence to HIV services, and ultimately infections and deaths averted, especially for interventions known to be effective.
The findings of this study have important financing implications. Although cost data are limited and the type of interventions too heterogeneous to determine a standard cost benchmark, the compiled evidence appears to justify an additional allocation of at least 5%, over and above the current 10% markup for critical enablers, to accommodate activities that address gender equality and GBV. This could initially require an overall increase in resource needs for the global HIV response, but it is likely that this investment could reduce future treatment costs and increase programme efficiency. Reallocating current spending may also be considered. That being said, there is increasing commitment from donors to make high-impact gender-responsive investments. For example, the Global Fund's new funding model requirements include a strong focus on gender-responsive programming and also encourage the use of grants to fill gaps relating to the cost of priority interventions that address gender inequality [102].
Interventions that tackle the structural drivers of HIV, such as inequalities in access to education, poor livelihoods and harmful gender norms commonly have multiple societal benefits, including for HIV. As such, the HIV sector should cofinance these interventions with other sectors, to ensure that all benefits are generated [91,103] and other development resources fully leveraged [104]. Given existing resource constraints, there will be growing emphasis on ensuring that available resources are used to best effect. Including costeffective, gender-responsive interventions in HIV portfolios will likely increase programme efficiency, as well as advance gender equity for more sustainable responses.