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Interventions to Prevent Sexually Transmitted Infections, Including HIV, Among Young People in Low- and Middle-Income Countries: A Systematic Review of the Published and Gray Literature

  • Amanda M. Kalamar
    Affiliations
    Department of Population Family and Reproductive Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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  • Angela M. Bayer
    Affiliations
    David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California

    Facultad de Salud Pública y Administración, Universidad Peruana Cayetano Heredia, Lima, Peru
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  • Michelle J. Hindin
    Correspondence
    Address correspondence to: Michelle J. Hindin, M.H.S., Ph.D., Johns Hopkins Bloomberg School of Public Health, Department of Population Family and Reproductive Health, 615 N. Wolfe Street, Baltimore, MD 21215.
    Affiliations
    Department of Population Family and Reproductive Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland

    Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland
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      Abstract

      Sexually transmitted infections (STIs), including HIV, are prevalent among adolescents and can have lasting adverse health consequences. The objective of this review is to identify high-quality interventions and evaluations to decrease STI transmission and related risky behaviors among young people in low- and middle-income countries. PubMed, Embase, PsycInfo, Cinahl Plus, Popline, and the Cochrane Databases were searched without language limitations for articles published through November 2015. Gray literature was searched by hand. Reference tracing was utilized, as well as the unpacking of systematic reviews. Retained articles were those that were evaluated as having high-quality interventions and evaluations using standardized scoring. Twenty-one high-quality interventions and evaluations were abstracted. Three reported declines in STI diagnoses, three reported declines in STI symptoms, six showed declines in risky sexual behavior, seven reported increases in abstinence, 11 found increases in condom use, and five reported increases in health care utilization. There is a wide range of rigorously evaluated high-quality interventions included in this review that can inform researchers, donors, and policy makers about where to make strategic investments to decrease the spread of STIs, including HIV. With the recent advent of biomarkers, researchers can use a gold standard measure to assess intervention impact. The diversity of interventions can allow decision makers to tailor interventions to the context, age range, and gender of the target population.

      Keywords

      Implications and Contribution
      This review finds 19 high-quality interventions and evaluations that reduce either sexually transmitted infections, including HIV, or related high-risk behaviors using a range of implementation strategies. The included studies can help inform strategic investments to reduce sexually transmitted infections across many contexts and among a diversity of populations.
      Young people, ages 10-24, and in particular females and members of key populations, are disproportionately impacted by HIV and other sexually transmitted infections (STIs). In 2013, of the 35 million people living with HIV globally, 4 million were aged 15–24 [
      UNAIDS
      The GAP report.
      ]. Globally, 15% of women living with HIV were aged 15–24, of whom 80% live in sub-Saharan Africa, the hardest hit region by the epidemic [
      UNAIDS
      Adolescent girls and young women.
      ]. There are approximately 380,000 new HIV infections among young women aged 15–24 every year, with 60% occurring in adolescent girls [
      UNAIDS
      Adolescent girls and young women.
      ]. Herpes simplex virus type 2 (HSV-2) is one of the most common STIs globally [
      • Looker K.J.
      • Garnett G.P.
      • Schmid G.P.
      An estimate of the global prevalence and incidence of herpes simplex virus type 2 infection.
      ], with the highest prevalence among 15- to 24-year olds found in sub-Saharan Africa followed by South Asia [
      • Looker K.J.
      • Garnett G.P.
      • Schmid G.P.
      An estimate of the global prevalence and incidence of herpes simplex virus type 2 infection.
      ]. HSV-2 has been suggested as a marker for sexual activity to overcome the bias in self-reported sexual behavior, particularly for young people [
      • Bastien S.
      • Mason-Jones A.J.
      • De Koker P.
      • et al.
      Herpes simplex virus type 2 infection as a biomarker for sexual debut among young people in sub-Saharan Africa: A literature review.
      ]. Young age is a major risk factor for certain STIs such as chlamydia, gonorrhea, and syphilis. For example, young age is the strongest predictor of chlamydia infection and prevalence of chlamydia is 3–4 times higher in females than in males [
      • Gewirtzman A.
      • Bobrick L.
      • Conner K.
      • et al.
      Epidemiology of sexually transmitted infections.
      ]. These data underscore the importance of focusing on prevention of STIs among adolescents and young people and particularly females and key populations.
      As was noted more than a decade ago, the majority of STIs occur in developing countries, and some of the key prevention and treatment strategies, including large-scale screening, face significant barriers [
      • Mayaud P.
      • Mabey D.
      Approaches to the control of sexually transmitted infections in developing countries: Old problems and modern challenges.
      ]. Understanding relationship and partner characteristics [
      • Swartzendruber A.
      • Zenilman J.M.
      • Niccolai L.M.
      • et al.
      It takes 2: Partner attributes associated with sexually transmitted infections among adolescents.
      ,
      • Mathur S.
      • Wei Y.
      • Zhong X.
      • et al.
      Partner characteristics associated with HIV acquisition among youth in Rakai, Uganda.
      ] is essential for STI prevention. STIs acquired during adolescence and young adulthood can have lasting health consequences if undiagnosed or untreated. These consequences can include transmission to multiple partners [
      • Wilson Chialepeh N.
      • Sathiyasusuman A.
      Associated risk factors of STIs and multiple sexual relationships among youths in Malawi.
      ], infertility [
      • Gottlieb S.L.
      • Low N.
      • Newman L.M.
      • et al.
      Toward global prevention of sexually transmitted infections (STIs): The need for STI vaccines.
      ], and pregnancy complications [
      • Gottlieb S.L.
      • Low N.
      • Newman L.M.
      • et al.
      Toward global prevention of sexually transmitted infections (STIs): The need for STI vaccines.
      ]. STIs are often asymptomatic, especially in males, who have few reasons to access health services, including STI screening. While a host of home-based [
      • Dukers-Muijrers N.H.
      • Theunissen K.A.
      • Wolffs P.T.
      • et al.
      Acceptance of home-based chlamydia genital and anorectal testing using short message service (SMS) in previously tested young people and their social and sexual networks.
      ] and point-of-care methods for screening are being developed [
      • Gaydos C.
      • Hardick J.
      Point of care diagnostics for sexually transmitted infections: Perspectives and advances.
      ], these methods are not widely available in low- and middle-income countries (LMICs). Prevention and treatment of STIs is challenging, as it most often requires both partners' involvement to reduce risky behavior (condom use and reduction of risky sexual practices), partner notification, and treatment to prevent reinfection. Overcoming these barriers is particularly acute for young people, who are often navigating complex relationships. Given the complexity of behavioral factors that contribute to STIs transmission, we systematically reviewed and evaluated interventions that were designed to reduce STI rates (primary outcome) and address the proximal behavioral outcomes of STI reduction strategies condom use, sexual activity, and health service utilization.
      Throughout this article, we include HIV as an STI, rather than a separate category.
      1Throughout this article, we include HIV as an STI, rather than a separate category.
      The objective of this systematic review is to identify high-quality interventions and evaluations to reduce STIs for young people in LMICs.

      Methods

      Search strategy

      We undertook a systematic search of published literature to identify interventions that address STIs in LMICs. We used six databases—PubMed (MEDLINE), Embase, PsycInfo, Cinahl Plus, Popline, and the Cochrane Databases—in conducting these searches. Search strategies for each database used the particular database's controlled vocabulary for searches (e.g., medical subject headings (Mesh) terms) as well as free text terms. In building the searches, we combined a list of terms that describe young people with a list of terms that describe STIs including HIV. We combined this search with a list of LMICs, as defined by the World Bank at the time of the search, and regional search terms. Details of the search strategy are described in the accompanying methodology commentary (Hindin and Kalamar, forthcoming).
      We also hand searched the gray literature targeting organizations involved in STI prevention strategies (for a complete listing see Hindin and Kalamar, forthcoming). We searched the literature from 2000 to November 2015.
      The results of the initial search of both published and gray literature were stored using EndNote (Thomson Reuters, Philadelphia, PA) reference manager software. All titles and abstracts resulting from the searches were screened for interventions related to STIs among 10- to 24-year olds in LMICs, and these remaining articles were abstracted.

      Inclusion/exclusion criteria

      Articles were included for abstraction if they met all the following criteria: (1) they report on STI interventions; (2) the intervention targeted young people, between ages 10 and 24; (3) the intervention was in an LMIC; (4) the article was written in English, French, Spanish, or Portuguese; and (5) the article was published from 2000 onward.

      Abstraction ranking strategy

      We created an abstracting and ranking template for all articles that met the inclusion criteria (available on request from the corresponding author). Each abstractor was given three sample articles, and the abstractions were reviewed for comparability. The abstraction template includes basic information on the design of the intervention and evaluation as well as a ranking of each. More detailed information is available from the methodology commentary (Hindin and Kalamar, forthcoming).
      For each of the abstracted articles, the quality of both the intervention and the evaluation of the intervention's effects were assessed and rated on a scale from 1 (weak) to 5 (strong). To assess the strengths and weaknesses of the intervention, reviewers were asked to consider whether the intervention was grounded in theory, if the intervention was first pilot tested to assess feasibility and acceptability, whether and what kind of training personnel involved in the intervention received, what steps were taken to prevent crossover or contamination between intervention and control groups, the duration of the intervention, and whether and how randomization of the intervention and/or evaluation took place. A ranking of 1 or 2 was given when the weaknesses of the intervention and study design heavily outweighed any identified strengths. Articles were ranked as a 3 when, on balance, the study design had about as many strengths as weaknesses. Those that were ranked as the strongest, 4 or 5, had more identified strengths than weaknesses, and those assigned a 5 had few, if any, weaknesses.
      To assess the strengths and weaknesses of the evaluation, reviewers were asked to consider several aspects of the evaluation design and evaluate the strengths and weaknesses before assigning a ranking score. These included the analytic techniques used to evaluate change attributable to the intervention, the use of an appropriate comparison group, sample size, operationalization and measurement of exposure to the intervention, length of follow-up, and the number of evaluation time points (particularly whether there was baseline and end-line data collection or just end line). To assign a ranking score (1–5) for the evaluation, the same methodology was used as for ranking the intervention.
      The quality of the intervention and evaluation of each included article was assessed by two reviewers, and discrepancies were arbitrated by a third reviewer. Each abstracted article then received a total score that combined both the intervention score and the evaluation score for a range of 2–10. Overall, articles were considered high quality if it had a total score of 8 or above and both the intervention score and evaluation score was at least a 4. Following this ranking process, only high-quality articles were retained, regardless of the intervention's impact on the outcome.

      Analysis

      The range of outcomes related to STI reduction strategies was not predefined or limited in scope during the search or data extraction process. The most common behavioral outcomes (Box 1) of the identified studies targeting STIs include condom use, abstinence or delaying initiation of sex or adoption of secondary abstinence for those who were already sexually active, limiting number of sexual partners, and STI testing or utilization of health services. While many studies included knowledge, norms, and behavioral outcomes, this review only includes articles with behavioral outcomes, as changes in knowledge and norms are not necessarily sufficient to produce behavior change. Due to the heterogeneity of the interventions, populations, and outcomes, a meta-analysis was not performed.
      Behavioral outcomes
      • Primary outcomes
        • STI diagnosis
        • STI symptomatology
      • Proximal outcomes
        • Risky sex (multiple partners/transactional sex)
        • Abstinence, secondary abstinence
        • Condom use
        • Utilization of health services
      The results are summarized to show the features of the interventions, populations, and impact of the interventions on STIs and related behaviors. Table 1 provides the description of the intervention and the key impact on the targeted behavior by outcome. The description includes the age range of participants at the time of the intervention, the duration of the intervention, the age range at the time of the evaluation, the venue of the intervention, and participant characteristics. Table 2 summarizes the findings of each article across all targeted behavioral outcomes, highlighting the main finding for each outcome.
      Table 1Description of high-quality sexually transmitted infections interventions and evaluations
      CountryInterventionEvaluationVenue and participantsMain intervention componentsImpact
      AgeLengthAge
      STI diagnosis (primary outcome)
       Malawi
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      13–222 years14–23Household: GirlsCash transfers conditioned on school attendance and payment of school fees+/--
       Kenya
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      13.5, on average5 months20.5, on averageSchool: Boys and girlsProvision of school uniforms; HIV curriculum (7-year follow-up)+/--
       South Africa
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      15–2613 months17–28Community: Boys and girlsSRH education curriculum via a participatory learning approach: 13 3-hour long sessions+/--
       Zimbabwe
      • Hallfors D.D.
      • Cho H.
      • Rusakaniko S.
      • et al.
      The impact of school subsidies on HIV-related outcomes among adolescent female orphans.
      123 years17School: Girls (orphaned)Payment of school fees; provision of school uniforms, books, and other school supplies (5-year follow-up)NS
      Self-reported STIs/symptoms (primary outcome)
       Malawi
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      10–24Not specified15–24Community/school: Boys and girlsCommunication program including radio program, listeners clubs, school presentations, magazine+
       Nigeria
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      14–1811 months12–25School: Boys and girlsHealth education curriculum; peer educators; training of medical professionals in diagnosis of STIs+
       Cameroon
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      None specified36 months15–24Community: Boys and girlsMass media campaign+/--
       Uganda
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      14–204 months16–22Community: GirlsLife-skills curriculum, vocational trainingNS
      Risky sexual activity: multiple partners (proximal outcome)
       Malawi
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      10–24Not specified15–24Community/school: Boys and girlsCommunication program including radio program, listeners clubs, school presentations, magazine+
       South Africa
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      9–1813 months10–19School: Boys and girlsSRH/STI curriculum: 12 one-hour modules+
       South Africa
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      None specifiedNot specified13–18Household: Boys and girlsUnconditional cash transfer program, eligibility determined by poverty level+
       Cameroon
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      None specified36 months15–24Community: Boys and girlsMass media campaign+/--
       Kenya
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      10–2436 months10–24Community: Boys and girlsHealth education curriculum: Weekly sessions for 4–8 weeks, 90–120 minutes per session+/--
       Kenya
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      None specifiedNot specified15–25Household: Boys and girlsUnconditional cash transfer program, eligibility determined by presence of an OVC or by poverty levelNS
       South Africa
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      15–2613 months17–28Community: Boys and girlsSRH education curriculum via a participatory learning approach: 13 three-hour long sessionsNS
       Kenya
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      15, on average8 months16, on averageSchool: Boys and girlsSRH education curriculum: national HIV curriculum or 1 two-hour risk reduction education session-
      Risky sexual activity: transactional sex (proximal outcome)
       Zimbabwe
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      None specified1 year10–24Community: Boys and GirlsMass media campaign+
       Kenya
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      None specifiedNot specified15–25Household: Boys and girlsUnconditional cash transfer program, eligibility determined by presence of an OVC or by poverty levelNS
       Malawi
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      10–24Not specified15–24Community/school: Boys and girlsCommunication program including radio program, listeners clubs, school presentations, magazineNS
       South Africa
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      15–2613 months17–28Community: Boys and girlsSRH education curriculum via a participatory learning approach: 13 three-hour long sessionsNS
       Kenya
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      15, on average8 months16, on averageSchool: Boys and girlsSRH education curriculum: national HIV curriculum or 1 two-hour risk reduction education session-
      Sexual activity/abstinence (proximal outcome)
       South Africa
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      16–2412 months16–26Community: Boys and girlsEntertainment education television drama series: 26 episodes+
       Zambia
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      None specified7 months13–19Community: Boys and girlsMass media campaign+
       Zimbabwe
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      None specified1 year10–24Community: Boys and girlsMass media campaign+
       Kenya
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      10–2436 months10–24Community: Boys and girlsHealth education curriculum: Weekly sessions for 4–8 weeks, 90–120 minutes per session+/--
       Malawi
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      10–24Not specified15–24Community/school: Boys and girlsCommunication program including radio program, listeners clubs, school presentations, magazine+/--
       Kenya
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      None specifiedNot specified15–25Household: Boys and girlsUnconditional cash transfer program, eligibility determined by presence of an OVC or by poverty level+/--
       South Africa
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      None specifiedNot specified13–18Household: Boys and girlsUnconditional cash transfer program, eligibility determined by poverty level+/--
       Bangladesh
      • Bhuyia I.
      • Rob U.
      • Chowdhury A.H.
      • et al.
      Improving adolescent reproductive health in Bangladesh.
      13–1918 months13–17Community/school: Boys and girlsSRH curriculum: 17 sessions; peer educatorsNS
       Malawi
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      13–222 years14–23Household: GirlsCash transfers conditioned on school attendance and payment of school feesNS
       South Africa
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      14, on average4 months15, on averageSchool: Boys and girlsSRH education curriculum: 12 weekly lessonsNS
       Kenya
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      15, on average8 months16, on averageSchool: Boys and girlsSRH education curriculum: national HIV curriculum or 1 two-hour risk reduction education session-
      Condom use (proximal outcome)
       Cameroon
      • Speizer I.S.
      • Tambashe B.O.
      • Tegang S.P.
      An evaluation of the “Entre Nous Jeunes” peer-educator program for adolescents in Cameroon.
      None specified18 months12–25Community: Boys and girlsMass media campaign; peer education+
       Cameroon
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      None specified36 months15–24Community: Boys and girlsMass media campaign+
       South Africa
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      16–2412 months16–26Community: Boys and girlsEntertainment education television drama series: 26 episodes+
       South Africa
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      9–1813 months10–19School: Boys and girlsSRH/STI curriculum: 12 one-hour modules+
       Uganda
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      14–204 months16–22Community: In and out-of school girlsLife-skills curriculum, vocational training+
       Zambia
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      None specified7 months13–19Community: Boys and girlsMass media campaign+
       Kenya
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      10–2436 months10–24Community: Boys and girlsHealth education curriculum: Weekly sessions with trained counselors for 4–8 weeks, 90–120 minutes per session+/--
       Nicaragua
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      None specified3 years15–26Community: Boys and girlsMass media campaign; youth leadership training+/--
       Nigeria
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      14–1811 months12–25School: Boys and girlsHealth education curriculum and campaign; peer educators; training of adolescent identified medical professionals in diagnosis of STIs+/--
       South Africa
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      14, on average4 months15, on averageSchool: Boys and girlsSRH education curriclum: 12 weekly lessons+/--
       Zimbabwe
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      None specified1 year10–24Community: Boys and girlsMass media campaign+/--
       Bangladesh
      • Bhuyia I.
      • Rob U.
      • Chowdhury A.H.
      • et al.
      Improving adolescent reproductive health in Bangladesh.
      13–1918 months13–17Community/school: Boys and girlsSRH curriculum: 17 sessions; peer educatorsNS
       Kenya
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      None specifiedNot specified15–25Household: Boys and girlsUnconditional cash transfer program, eligibility determined by presence of an OVC or by poverty levelNS
       Kenya
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      13.5, on average5 months20.5, on averageSchool: Boys and girlsProvision of school uniforms; HIV curriculum (7-year follow-up)NS
       Kenya
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      15, on average8 months16, on averageSchool: Boys and girlsSRH education curriculum: national HIV curriculum or 1 risk reduction session of approximately 2 hoursNS
       Malawi
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      13–222 years14–23Household: GirlsCash transfers conditioned on school attendance and payment of school feesNS
       South Africa
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      15–2613 months17–28Community: Boys and girlsSRH education curriculum via a participatory learning approach: 13 three-hour long sessionsNS
      Health services utilization (proximal outcome)
       Nicaragua
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      None specified3 years15–26Community: Boys and girlsMass media campaign; youth leadership training+
       Nigeria
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      14–1811 months12–25School: Boys and girlsHealth education curriculum and campaign; peer educators; training of adolescent identified medical professionals in diagnosis of STIs+
       South Africa
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      16–2412 months16–26Community: Boys and girlsEntertainment education television drama series: 26 episodes+
       Tanzania
      • Larke N.
      • Cleophas-Mazige B.
      • Plummer M.L.
      • et al.
      Impact of the MEMA kwa Vijana adolescent sexual and reproductive health interventions on use of health services by young people in rural Mwanza, Tanzania: Results of a cluster randomized trial.
      None specified2 years15–24Community and facility: Boys and girlsSRH education curriculum; provision of adolescent friendly reproductive health services; condom distribution+
       Zimbabwe
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      None specified1 year10–24Community: Boys and girlsMass media campaign+
       Malawi
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      13–222 years14–23Household: GirlsCash transfers conditioned on school attendance and unconditional cash transfersNS
       Uganda
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      14–204 months16–22Community: GirlsLife-skills curriculum, vocational trainingNS
      Studies appear more than once when there are multiple measured outcomes.
      + = statistically significant positive effect; +/-- = mixed effects; - = statistically significant negative effect; NS = no statistically significant effect; OVC = orphan or vulnerable child; SRH = sexual and reproductive health; STIs = sexually transmitted infections.
      Table 2Impact summary of high-quality sexually transmitted infections interventions and evaluations
      CountryInterventionBehavioral outcome

      STIsRisky sexual behavior
      STI diagnosis (decrease expected)Self-reported STIs/symptoms (decrease expected)Multiple partners (decrease expected)Transactional sex (decrease expected)Condom use (increase expected)Abstinence (increase expected)Health services utilization (increase expected)
      Kenya
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      Health education curriculum
      Among girls; no impact among boys.
      Among boys; no impact among girls.
      Among girls; no impact among boys.
      Kenya
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      Health education curriculum
      Among boys; no impact among girls.
      Among boys; no impact among girls.
      Among girls; no impact among boys.
      Nigeria
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      Health education curriculum
      Among girls; no impact among boys.
      South Africa
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      SRH/STI curriculum
      South Africa
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      SRH curriculum
      Increase in condom use; no impact on condom use consistency.
      Tanzania
      • Larke N.
      • Cleophas-Mazige B.
      • Plummer M.L.
      • et al.
      Impact of the MEMA kwa Vijana adolescent sexual and reproductive health interventions on use of health services by young people in rural Mwanza, Tanzania: Results of a cluster randomized trial.
      SRH curriculum
      Bangladesh
      • Bhuyia I.
      • Rob U.
      • Chowdhury A.H.
      • et al.
      Improving adolescent reproductive health in Bangladesh.
      SRH curriculum
      Cameroon
      • Speizer I.S.
      • Tambashe B.O.
      • Tegang S.P.
      An evaluation of the “Entre Nous Jeunes” peer-educator program for adolescents in Cameroon.
      Peer education program
      Uganda
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      Life-skills training
      South Africa
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      Entertainment education television programming
      Cameroon
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      Mass media campaign
      Among boys; not measured for girls.
      Among girls; no impact among boys.
      Malawi
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      Mass media campaign
      Increase in rural site; no impact in urban site.
      Nicaragua
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      Mass media campaign
      Increase among those with casual partners; no impact among those with steady partners.
      Results from qualitative data; no effect significance.
      South Africa
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      Mass media campaign
      Decrease in HSV-2 incidence; no impact on HIV incidence.
      Zambia
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      Mass media campaign
      Zimbabwe
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      Mass media campaign
      Kenya
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      Unconditional cash transfers
      Among girls; no impact among boys.
      Malawi
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      Conditional cash transfers
      Among in-school youth; no effect among out-of school; no effect on syphilis in either groups.
      South Africa
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      Unconditional cash transfers
      Among girls; no impact among boys.
      Kenya
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      School uniforms; HIV curriculum
      Among girls; no impact among boys.
      HSV-2: When two intervention programs were delivered jointly; no effect on HIV.
      Zimbabwe
      • Hallfors D.D.
      • Cho H.
      • Rusakaniko S.
      • et al.
      The impact of school subsidies on HIV-related outcomes among adolescent female orphans.
      School fees, uniforms, book, and supplies
       = effect significant at p < .05;  = effect significant at p < .01;  = effect significant at p < .001.
      HSV-2 = Herpes simplex virus type 2; SRH = sexual and reproductive health; STI = sexually transmitted infection.
      a Among girls; no impact among boys.
      b Among boys; no impact among girls.
      c Among boys; no impact among girls.
      d Increase in condom use; no impact on condom use consistency.
      e Among boys; not measured for girls.
      f Increase in rural site; no impact in urban site.
      g Increase among those with casual partners; no impact among those with steady partners.
      h Results from qualitative data; no effect significance.
      i Decrease in HSV-2 incidence; no impact on HIV incidence.
      j Among in-school youth; no effect among out-of school; no effect on syphilis in either groups.
      k HSV-2: When two intervention programs were delivered jointly; no effect on HIV.

      Results

      Figure 1 is a flow diagram showing the identification, screening, and inclusion of articles. The initial search strategy yielded more than 23,000 articles of which 133 were retained after title and abstract screening. Of these 133 studies, 70 were low-quality interventions and removed, 39 were low-quality evaluations and removed, and three were previous evaluations of an intervention and removed, keeping the most recent evaluation of that intervention. At the end of this process, 21 high-quality studies were retained, all with at least one behavioral outcome.

      Quality of the evidence

      High-quality interventions often included relevant stakeholders in the design and implementation of the intervention, a pilot phase or formative work, a theory of change and were well planned and organized with sufficient detail on both intervention components and the implementation. Lower quality interventions had limitations that outweighed strengths including limited information about the intervention and the activities, flaws in the intervention design including the intervention being too short, limited information on the process of implementation and potential implementation problems, or there was simply not enough intervention detail to draw conclusions on its strengths and weaknesses.
      High-quality evaluations were rigorous, accounted for exposure levels to intervention activities, used sophisticated analyses, employed randomization, and appropriate control groups. Weaker evaluations often had limited information on analysis and results, high loss-to-follow-up rates in longitudinal studies, inability to control for contamination in the analysis, limited statistical power and analytic techniques, no measure of exposure to the intervention, and no or an inappropriate comparison group.

      Primary outcomes

      We identified eight articles [
      • Hallfors D.D.
      • Cho H.
      • Rusakaniko S.
      • et al.
      The impact of school subsidies on HIV-related outcomes among adolescent female orphans.
      ,
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      ,
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ] that measured STI symptomatology or diagnosis as the outcome either through testing or clinical diagnosis [
      • Hallfors D.D.
      • Cho H.
      • Rusakaniko S.
      • et al.
      The impact of school subsidies on HIV-related outcomes among adolescent female orphans.
      ,
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      ] or by self-report diagnosis or symptomatology [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ] (Tables 1 and 2).

      STI diagnosis

      Four articles reported outcomes based on testing or clinical diagnosis [
      • Hallfors D.D.
      • Cho H.
      • Rusakaniko S.
      • et al.
      The impact of school subsidies on HIV-related outcomes among adolescent female orphans.
      ,
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      ]. Of these four, only one showed significant decreases in HIV and HSV-2 [
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ], although only among girls that were enrolled in school at the start of the intervention; two found a decrease in HSV-2 but no impact on HIV [
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      ]. The remaining intervention had no impact on HIV or HSV-2 [
      • Hallfors D.D.
      • Cho H.
      • Rusakaniko S.
      • et al.
      The impact of school subsidies on HIV-related outcomes among adolescent female orphans.
      ]. The one article with significant impact on both HIV and HSV-2 based on testing was a conditional transfer program [
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ].

      Self-reported STI diagnosis/symptomatology

      Four interventions were identified that measured self-reported symptoms of STIs [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ]. One article used self-report data on having an STI in the last 12 months [
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ] and found the intervention led to significant declines in these reports using a mass media campaign. Two found that the intervention led to decreased reporting of STI symptoms [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ], while the third had no statistical impact on reported symptoms [
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ]. The two interventions with positive impacts on STI symptomatology were a mass media campaign and a school-based education curriculum [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ], while the third with no statistical impact used a life-skills curriculum [
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ].

      Proximal outcomes

      We include five outcomes that are proximal to decreasing STI acquisition. Multiple partners and transactional sex are risky sexual behaviors. Primary or secondary abstinence and never/ever having sex are classified as abstinence/sexual activity. Fourth is self-reported condom use and lastly health utilization, which includes the use of services for testing, treatment, and prevention.

      Risky sexual behaviors

      Nine articles [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ] included outcomes related to having multiple partners and/or transactional sex.

      Multiple partners

      Of the nine identified articles with risky sex as an outcome, eight measured multiple partners as an outcome [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      ,
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ]. Five included interventions that found significant declines in reports of multiple partnerships [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ], two had no impact [
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ], while the eighth showed significant increases in multiple partners among boys [
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ]. Of the interventions that significantly decreased reports of multiple partners, two were mass media campaigns [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ], two were curriculum based [
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ], and one was an unconditional cash transfer program [
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ].

      Transactional sex

      Five of the articles reported on transactional sex as an outcome [
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ]. Among these, only one [
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ], a mass media campaign, significantly decreased transactional sex while one of these, a very short risk reduction curriculum, found an increase in transactional sex among boys [
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ].

      Abstinence/sexual activity

      Eleven articles [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ,
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      ,
      • Bhuyia I.
      • Rob U.
      • Chowdhury A.H.
      • et al.
      Improving adolescent reproductive health in Bangladesh.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ] include outcomes related to sexual activity—either primary/secondary abstinence, or ever/never having sex. For easier comparisons, we refer to increases in never having sex or decreases in ever having sex as increases in primary abstinence. Of identified articles, seven found increased abstinence [
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ] although not uniformly across subgroups (e.g., [
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ] for girls only and [
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ] rural only). The successful intervention strategies (n = 7) for abstinence included mass media campaigns (n = 4, [
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ]), a health curriculum intervention (n = 1, [
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ]), and unconditional cash transfers (n = 2, [
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Heinrich C.J.
      • Brill R.
      Stopped in the name of the law: Administrative burden and its implications for cash transfer program effectiveness.
      ]).

      Condom use

      Seventeen articles [
      • Speizer I.S.
      • Tambashe B.O.
      • Tegang S.P.
      An evaluation of the “Entre Nous Jeunes” peer-educator program for adolescents in Cameroon.
      ,
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      ,
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ,
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      ,
      • Bhuyia I.
      • Rob U.
      • Chowdhury A.H.
      • et al.
      Improving adolescent reproductive health in Bangladesh.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ] looked at self-reported condom use including at last sex, consistent use, or ever condom use as outcomes. Twelve articles [
      • Speizer I.S.
      • Tambashe B.O.
      • Tegang S.P.
      An evaluation of the “Entre Nous Jeunes” peer-educator program for adolescents in Cameroon.
      ,
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ,
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ] found a statistically significant impact on condom use. Of these 12, five were not a uniformly positive impact ([
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ] girls only, [
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ] boys only, [
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ]casual partner but not with regular partner, [
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      ] with general condom use but not consistent use, and [
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ] condom use but not asking a partner to use a condom). Of the twelve successful interventions, six were mass media campaigns [
      • Speizer I.S.
      • Tambashe B.O.
      • Tegang S.P.
      An evaluation of the “Entre Nous Jeunes” peer-educator program for adolescents in Cameroon.
      ,
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ], five were health or life-skills curricula [
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ,
      • Jemmott 3rd, J.B.
      • Jemmott L.S.
      • O'Leary A.
      • et al.
      School-based randomized controlled trial of an HIV/STD risk-reduction intervention for South African adolescents.
      ,
      • Erulkar A.S.
      The experience of sexual coercion among young people in Kenya.
      ,
      • Taylor M.
      • Jinabhai C.
      • Dlamini S.
      • et al.
      Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa.
      ], and one was an unconditional cash transfer programs to eligible households [
      • Handa S.
      • Halpern C.T.
      • Pettifor A.
      • et al.
      The government of Kenya's cash transfer program reduces the risk of sexual debut among young people age 15-25.
      ]. The six without significant impact were education curricula (n = 2) [
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Bhuyia I.
      • Rob U.
      • Chowdhury A.H.
      • et al.
      Improving adolescent reproductive health in Bangladesh.
      ], a mass media campaign [
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ], and cash transfers or school support (n = 3).

      Health services utilization

      Interventions that encourage seeking health services are important for the provision of condoms and diagnosis and treatment of STIs. Of the seven articles that looked at health care utilization [
      • Larke N.
      • Cleophas-Mazige B.
      • Plummer M.L.
      • et al.
      Impact of the MEMA kwa Vijana adolescent sexual and reproductive health interventions on use of health services by young people in rural Mwanza, Tanzania: Results of a cluster randomized trial.
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ], five [
      • Larke N.
      • Cleophas-Mazige B.
      • Plummer M.L.
      • et al.
      Impact of the MEMA kwa Vijana adolescent sexual and reproductive health interventions on use of health services by young people in rural Mwanza, Tanzania: Results of a cluster randomized trial.
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ] reported a positive impact on health services utilization. Three reported an increase in seeking or use of services [
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ] one reported increases in HIV testing [
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ], and one on STI treatment [
      • Larke N.
      • Cleophas-Mazige B.
      • Plummer M.L.
      • et al.
      Impact of the MEMA kwa Vijana adolescent sexual and reproductive health interventions on use of health services by young people in rural Mwanza, Tanzania: Results of a cluster randomized trial.
      ]. The impactful interventions include three mass media campaigns [
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ] and two curriculum-based interventions [
      • Larke N.
      • Cleophas-Mazige B.
      • Plummer M.L.
      • et al.
      Impact of the MEMA kwa Vijana adolescent sexual and reproductive health interventions on use of health services by young people in rural Mwanza, Tanzania: Results of a cluster randomized trial.
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ]. The two interventions which found no impact on health services utilization were a conditional cash transfer program [
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ] and a life-skills curriculum with vocational training [
      • Banderia O.
      • Buehern N.
      • Burgess R.
      • et al.
      Empowering adolescent girls: Evidence from a randomized control trial in Uganda.
      ].

      Discussion

      STIs, including HIV, disproportionately impact the health of young people in LMICs, and many are readily preventable and treatable. Significant resources to treat and prevent HIV have been spent, but other STIs have received limited attention. Overall, of the nearly 23,000 published titles screened, we only retained 15 articles (.07%) that met our criteria with an additional six high-quality articles found in the gray literature. Measures of STI diagnosis, based on biological data, are increasingly included in the newer evaluations and provide a “gold standard” measure of intervention impact. When using STI diagnosis as an intervention outcome measure, we find three studies that had a statistically significant impact on STI prevalence (two cash transfer or education support programs and a mass media campaign) [
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Duflo E.
      • Dupas P.
      • Kremer M.
      Education, HIV and early fertility: Experimental evidence from western Kenya.
      ], and three interventions with self-reported STIs and symptoms were significantly associated with the reported outcomes [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Okonofua F.E.
      • Coplan P.
      • Collins S.
      • et al.
      Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths.
      ]. Three of the included articles note caution in interpreting the results related to prevalence or incidence of STIs as the population prevalence or incidence was found to be lower than expected when the intervention was designed, these studies were not powered to detect smaller changes [
      • Hallfors D.D.
      • Cho H.
      • Rusakaniko S.
      • et al.
      The impact of school subsidies on HIV-related outcomes among adolescent female orphans.
      ,
      • Baird S.J.
      • Garfein R.S.
      • McIntosh C.T.
      • et al.
      Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: A cluster randomised trial.
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ].
      We considered four proximal outcomes to STI diagnosis and transmission—risky sexual behavior including multiple partner and transactional sex, condom use, sexual activity/abstinence, and health services utilization. Some of the strongest associations with risky sexual behaviors were seen with mass media campaigns [
      • Plautz A.
      • Meekers D.
      Evaluation of the reach and impact of the 100% Jeune youth social marketing program in Cameroon: Findings from three cross-sectional surveys.
      ,
      • Manyonga V.
      Malawi HIV/AIDS TRaC study evaluating abstinence among unmarried youth (15-24 years).
      ,
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ,
      • Kim Y.M.
      • Kols A.
      • Nyakauru R.
      • et al.
      Promoting sexual responsibility among young people in Zimbabwe.
      ,
      • Kelly K.
      • Parker W.
      • Hajiyiannis H.
      • et al.
      Tsha Tsha: Key findings of the evaluation of episodes 1-26.
      ,
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ,
      • Solórzano I.
      • Bank A.
      • Peña R.
      • et al.
      Catalyzing personal and social change around gender, sexuality, and HIV: Impact evaluation of Puntos de Encuentro's communication strategy in Nicaragua.
      ]—these types of interventions have been shown elsewhere to be very effective in changing knowledge, attitudes, and self-reported behavior [
      • Bertrand J.T.
      • Anhang R.
      The effectiveness of mass media in changing HIV/AIDS-related behaviour among young people in developing countries.
      ,
      • Delgado H.M.
      • Austin S.B.
      Can media promote responsible sexual behaviors among adolescents and young adults?.
      ]. Similar to the issues surrounding STI diagnosis compared with self-reported data, measures of risky sexual behavior, condom use, and sexual activity are subject to social desirability bias. Although evaluations are becoming more sophisticated with Audio Computer Assisted Interviews and other techniques to promote confidentiality, sensitive behaviors around sexual activity continue to be underreported, particularly after interventions that “tell” respondents the “correct” responses to questions. Biological evidence is significantly more reliable than self-reported data [
      • Hewett P.C.
      • Mensch B.S.
      • Ribeiro M.C.
      • et al.
      Using sexually transmitted infection biomarkers to validate reporting of sexual behavior within a randomized, experimental evaluation of interviewing methods.
      ,
      • Kelly C.A.
      • Hewett P.C.
      • Mensch B.S.
      • et al.
      Using biomarkers to assess the validity of sexual behavior reporting across interview modes among young women in Kampala, Uganda.
      ,
      • Mensch B.S.
      • Soler-Hampejsek E.
      • Kelly C.A.
      • et al.
      Challenges in measuring the sequencing of life events among adolescents in Malawi: A cautionary note.
      ], especially for stigmatized behavior such as sexual activity. Health services utilization, our final proximal outcome, is often difficult to monitor and trace back to the intervention, unless specific questions are included about source of referral or direct questions on health care utilization. In addition, in many settings, condoms are widely available in nonhealth settings, and so the impact of interventions to provide condoms are likely underestimated.
      The most commonly targeted behavior was condom use, with 12 of the 17 articles finding a positive impact. These 12 articles represent a large variety in intervention designs, suggesting that there is no single “magic bullet” intervention and that the appropriate intervention for the context and population can be chosen. Similarly, the types of intervention designs with positive findings for multiple partners, abstinence, and health services utilization are wide ranging. Transactional sex seemed to be the most difficult behavior to change, with only one of the four interventions, a mass media campaign, finding a statistically significant decrease.
      Health education and sexual and reproductive health (SRH)/STI education curricula were the most common intervention design (n = 8), most often targeting condom use, largely with success. Mass media campaigns were frequently used to target a range of outcomes (n = 7), also largely with success. This is in line with others that have found mass media campaigns effective in changing self-reported behaviors [
      • Bertrand J.T.
      • Anhang R.
      The effectiveness of mass media in changing HIV/AIDS-related behaviour among young people in developing countries.
      ]; however, these intervention designs rarely focused on the gold standard of biological outcomes. Cash transfer and educational support programs were also a common intervention design (n = 5) focusing on multiple outcomes with mixed success. This may be because these programs are largely designed to keep girls in school rather than with an explicit focus on STI prevention.
      Several of the articles additionally report on unintended effects that should be considered. Some found outcome effects in the direction opposite than expected. Dupas [
      • Dupas P.
      Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya.
      ] finds an increase in multiple partners and increase in transaction sex among boys, hypothesizing that the girls in the intervention may have substituted older men for their classmates, possibly the intervention boys. Jewkes et al. [
      • Jewkes R.
      • Nduna M.
      • Levin J.
      • et al.
      Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: Cluster randomised controlled trial.
      ] find an increase in transactional sex among women at the 12-month follow-up, but this increase is no longer statistically significant at 24 months (the reported finding in this review). Underwood et al. [
      • Underwood C.
      • Hachonda H.
      • Serlemitsos E.
      • et al.
      Reducing the risk of HIV transmission among adolescents in Zambia: Psychosocial and behavioral correlates of viewing a risk-reduction media campaign.
      ] found that those reporting high levels of perceived risk were more likely to say they were sexually active, not always using a condom, and not practicing safe sex—that the intervention helped them to realize their risk but not change their related behaviors. Others report unanticipated effects not related to the measured outcomes. For example, one of the implemented SRH curriculum interventions found that at endline, the intervention group was less likely to support the introduction of SRH curriculum into schools [
      • Bhuyia I.
      • Rob U.
      • Chowdhury A.H.
      • et al.
      Improving adolescent reproductive health in Bangladesh.
      ]. The authors hypothesize that the control group may still imagine the curriculum as potentially being useful while the intervention group may not have had their expectations met.
      There are a number of limitations from this review to consider. As discussed earlier, despite having high-quality evaluations, self-reported data remain a far from perfect measure of outcomes. With the introduction of relatively inexpensive, noninvasive, and rapid testing for STIs, we anticipate more projects to include biological measures, which provide much more reliable data. Intervention cost and cost-effectiveness analysis were not included in most of the articles so it is difficult to assess their sustainability and scale-up potential. This is particularly true for use of biomarkers. Future interventions that include biological outcomes should consider presenting cost data to allow researchers to assess the potential for replication in other settings and populations.
      Although we grouped interventions by outcome, even within outcomes, there is significant heterogeneity. For example, condom use was defined as ever use, consistent use, and use at last sex while transactional sex included avoiding “sugar daddies” or reporting avoidance of a sexual encounter if no items were received. This variation makes it difficult to directly compare interventions, though the mostly positive findings for these outcomes suggest that there are a range of intervention strategies that are promising despite these varied definitions. In addition, although we include both gray and published literature, and did not limit our reporting to only positive results, it is likely that some interventions with null findings were never reported. Finally, we include the most recent evaluation of a particular intervention with the same outcome. For example, if a group reported on short term and longer term follow-up, we use the most recent report on the intervention and its impact. This limitation is important to consider as some interventions may have short-term impact but not long-term impact (or vice versa). This decision was made to avoid redundancy but may not fully represent all the effects of a given intervention.
      There is a wide range of high-quality interventions that worked included in this review which can inform researchers, donors, and policymakers about where to make strategic investments to decrease the spread of STIs, including HIV, while avoiding replication of interventions that were well designed and evaluated but did not result in behavior change. While replication in new populations should be done with caution and careful consideration of the context, this review points to a range of interventions and outcomes that can be considered. With the recent advent of biomarkers increasingly seen in the more recent evaluations, researchers, donors, and policymakers can use a gold standard measure of impact moving forward. The diversity of intervention designs and behavioral outcomes targeted can aid decision makers in tailoring evidence-based interventions to the context, age range, and gender of the target population.

      Acknowledgments

      Advisory Committee: Bob Blum, Bruce Dick, and Jane Ferguson. Review Team: A.M.K., A.M.B., Akin Omisore, Carie Cox Muntifering, Jaya, Hannah Lantos, Susan Lee-Rife, Terri-Ann Thompson, and Ushma Upadhyay and Virginia Bowen. M.J.H. and Adesegun O. Fatusi were Principal Investigators.

      Funding Sources

      This work was supported by a grant to Johns Hopkins Bloomberg School of Public Health, Department of Population, Family and Reproductive Health from the John D. and Catherine T. MacArthur Foundation .

      References

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