Supporting young womens health through girl-friendly drug vendors in Lake Zone, Tanzania: protocol for the AmbassADDOrs for Health cluster-randomised controlled trial


Adolescent girls and young women (AGYW; aged 15–24 years) are disproportionately affected by HIV infection and unintended pregnancy in sub-Saharan Africa. There, approximately 44% of the 14 million unintended pregnancies that occur annually worldwide and nearly 20% of incident HIV cases were among AGYW aged 15–24 years, despite them comprising just 10% of the population.1 In Tanzania, nearly one-third of pregnancies occur in AGYW, 23% have unmet need for contraception and 2.1% of AGYW live with HIV.2 3 AGYW face unique challenges in accessing HIV and sexual and reproductive health (SRH) care, including inability to pay for transport or related costs, concerns about privacy and sparsely available AGYW-centred care.4 5 Limited access to and uptake of SRH services among AGYW6 hinders the potential of current and upcoming HIV prevention and SRH strategies such as new formulations for HIV pre-exposure prophylaxis (PrEP)7 or self-injectable contraception.8

While public health facilities fill an important role in SRH care in lower-income countries, interest in other avenues for healthcare provision via private sector channels,9–12 such as small drug shops and pharmacies, is growing.13–17 Community drug shops sell medicine and health products (eg, hygiene, vitamins)13 15 18 and, in lower-income countries, provide over half of all healthcare and are often the only access point in underserved areas.18 Since they effectively expand health systems’ reach and are a gateway to clinical care, many countries are training this cadre to deliver priority initiatives (eg, SRH, diarrhoea, malaria).15 16 19–29 Tanzania’s Accredited Drug Dispensing Outlet (ADDO) Programme is a model for formalising this sector. ADDOs are in nearly every community and can improve access to quality-assured pharmaceuticals, including contraceptives.30 31 For example, adding malaria services to ADDOs’ workflow has improved proper dispensing of antimalarial drugs,32–34 demonstrating the promise of the ADDO platform.

To lower HIV incidence and unintended pregnancy among AGYW, we must first increase access to and uptake of contraceptives and HIV prevention, with HIV testing as a critical gateway.35 Compared with adults, AGYW are less aware of their HIV status despite available testing at clinics.36–38 WHO-recommended HIV self-tests (HIVST) using oral fluid kits are effective for safe and confidential testing.39 40 Studies in Malawi, Zimbabwe and Zambia show high demand for HIVST, especially among adolescents.41–44 Further, better access to contraception at drug shops is an underexplored yet potentially effective strategy for addressing unmet need among AGYW; though overall contraceptive demand is low among AGYW (19%) compared with older women (35%) in Tanzania,45 national data show that AGYW are twice as likely as older women to obtain contraceptives from drug shops. ADDOs provide a largely untapped opportunity to reach AGYW with these underused prevention products, including HIVST and contraceptives; and new strategies are needed to drive demand among AGYW and simultaneously provide girl-friendly safe spaces to learn about and access these products.

Intervention design, theoretical foundation and pilot study

From 2018 to 2019, we used a process integrating human-centred design (HCD) and behavioural economics to develop the Malkia Klabu (Queen Club) intervention. Throughout each stage of the design process (figure 1),46 complementary approaches from HCD and behavioural economics were considered within the context of future scalability of Malkia Klabu. The design process is described in detail elsewhere47; the outcome of this formative work was Malkia Klabu, an enhanced loyalty programme whereby AGYW members can receive free contraceptives (oral pills, emergency contraception, condoms), urine pregnancy tests and HIVST kits while earning punches for shop purchases that can be redeemed for small prizes of increasing value (eg, soap, nail polish).

Figure 1
Figure 1

Logic model outlining intervention framework. ADDOs, Accredited Drug Dispensing Outlets; AGYW, adolescent girls and young women; HIVST, HIV self-test; SRH, sexual and reproductive health.

Using a rigorous mixed-methods implementation science evaluation framework, we subsequently tested the feasibility and acceptability of Malkia Klabu in 2019 via a 4-month pilot randomised controlled trial among 40 shops (1:1 intervention/control). We found that shops implementing Malkia Klabu had 4.4 times the number of AGYW customers, distributed over twice as many HIVST kits, 46 times higher contraceptives and 7 times more referrals for clinic-based SRH services relative to business-as-usual comparison shops.48 At the same time, inconsistencies in shopkeepers’ records highlighted the need for better systematic inventory management and sales documentation as the intervention was readied for scale. Nevertheless, these findings demonstrate the feasibility and acceptability of Malkia Klabu among AGYW and shopkeepers. Importantly, we affirmed that the multifaceted solutions incorporated into the intervention served to overcome a number of structural and behavioural barriers for both sets of actors. We describe our planned study protocol involving a cluster-randomised controlled trial (c-RCT) over 24 months (Standard Protocol Items: Recommendations for Interventional Trials checklist in online supplemental appendix 1).

Supplemental material

Regionally scaled effectiveness study

This study builds on our pilot study and will directly measure effectiveness of the Malkia Klabu Programme when regionally scaled, while also including metrics to understand adaptability (figure 1). We describe our planned study protocol involving a c-RCT over 24 months.


Study design

We will conduct a 24-month, unblinded, parallel two-arm type 1 effectiveness implementation49 c-RCT of the Malkia Klabu Programme in approximately 40 health facility catchment areas to achieve the following study aims:

  • Aim 1: at the population level, evaluate the effectiveness of the Malkia Klabu Programme on HIV diagnoses and antenatal care (ANC) registrations among AGYW in Lake Zone, Tanzania.

  • Aim 2: verify individual-level behaviour change, including recent HIV testing, unmet need for contraception and linkage to care, and describe demand-side pathways (eg, Malkia Klabu reach into AGYW networks) through which Malkia Klabu may reduce HIV and unintended pregnancy among AGYW.

  • Aim 3: understand supply-side innovations and challenges, and determine how implementation fidelity relates to programme effectiveness. We will use a mixed-methods implementation science study to pinpoint supply-side factors influencing effectiveness (eg, implementation models, programme fidelity, shop characteristics).

Study setting

The study will take place in the Shinyanga and Mwanza provinces in the Lake Zone of Tanzania (figure 2). Shinyanga has a population size of 2.2 million and Mwanza is a home to 3.7 million people according to the 2022 national census report,50 with 835 and 438 health facilities in each province, respectively, the majority of which (56.4% and 7.9%, respectively) were dispensaries. In Tanzania, 22% of women aged 15–19 years have ever been pregnant, with the proportion of pregnancies among AGYW higher in rural versus urban areas (24.9% vs 16.4%) as well as in our study regions, where 16.3% in Mwanza and 20.8% in Shinyanga of women aged 15–19 years have ever been pregnant.51 A recent study of over 400 pregnant AGYW seeking care at ANC clinics in Mwanza found that nearly half tested positive for at least one of six common sexually transmitted infections (STIs).52 The Shinyanga region has the second highest HIV prevalence in Tanzania where 6.2% of AGYW are living with HIV compared with the national average of 3.7%.53

Figure 2
Figure 2

Study area.

Study arms

To facilitate monitoring and management of general sales data in all ADDO shops as well as the Malkia Klabu Programme processes in intervention shops, the study is collaborating with Maisha Meds, a point-of-sale inventory management system,54 to provide the tablet-based system to participating ADDOs free of charge to facilitate collection and analysis of sales data. All eligible ADDO shops in selected catchment areas willing to participate will receive additional Maisha Meds training during their study training.

In both arms, ADDO staff will be trained to answer questions about HIVST and contraception, and give referrals to specific local study-affiliated public health facilities for confirmatory HIV testing, PrEP, long-acting reversible contraceptives (LARCs; for example, intrauterine devices, implants), ANC, STI services and general SRH services.

Intervention arm

The intervention arm will retain the components of Malkia Klabu developed and tested in the pilot, including the use of a loyalty card (online supplemental appendix 2), gifting a free, opt-out HIVST kit upon sign up, giving free SRH products (oral contraceptives, emergency contraception, condoms, HIVST kits and urinary pregnancy tests) upon request and allowing punches on their card for purchases that can be redeemed for two levels of prizes at future visits.

Supplemental material

Consenting and enrolled intervention shops will receive comprehensive, 2-day training to review the objectives of the study, the Malkia Klabu Programme, as well as training in providing girl-friendly services, HIVST kits and how to use the Maisha Meds system. Intervention shops will have referrals for female youth-friendly clinicians who are already stationed at the health facility and will attend a study training focused on the provision of girl-friendly SRH care, as well as peer navigators in the study-affiliated public health facilities. Both peer navigators and the youth-friendly clinicians will log the interactions, noting service requested and services provided, including further referrals, and linking each record to a Malkia Klabu ID without collecting any other identifiers.

Upon completing training, ADDOs will receive all the commodities necessary to implement Malkia Klabu in their shop, including a 1-month supply of HIVST kits reserved for free distribution to AGYW who opt into Malkia Klabu. The kits will be prepackaged with specific referral information and their distribution will be tracked in Maisha Meds along with all other study-related and non-study-related sales of products. Further, all ADDO staff will be regularly reimbursed at fixed prices for the SRH products provided freely to Malkia Klabu members (condoms, oral contraceptives, emergency contraception and pregnancy tests), but which will be independently procured by shops per business as usual; the study will provide HIVST kits.

In addition to the facility-based youth-friendly clinician, ADDO shops randomised to intervention catchment areas will receive contact information for one to two local peer navigators who will facilitate linkage to care to the study-affiliated referral health facility. Peer navigators will be recruited in one of two ways: (1) AGYW already working at referral facilities in a similar role and (2) community volunteers recruited through referrals from community leaders.

Control arm

Shops enrolled in the control arm will receive separate (from intervention shops) 1-day training on HIVST kits and the use of the Maisha Meds system, as well as a 1-month supply (eligible for restocking) of HIVST kits marked for free distribution to AGYW (to be tracked in Maisha Meds) with non-specific referral information to a nearby public referral facility. Contraceptives and pregnancy tests will be procured and sold as per normal business operations.


Approximately 40 catchment areas will be recruited. Starting with a listing of government health facilities in the study regions, the sampling frame will only include catchment areas with three public health facilities or less, at least one of which offers both HIV and ANC services, to ensure accessibility to these services while facilitating data collection for our primary outcome and thus clearer attribution of population-level effects to the intervention. Catchment areas will be randomly assigned 1:1 to intervention or comparison arms within strata of region, population density and antiretroviral therapy (ART) caseload using a constrained randomisation approach to ensure balance in these key covariates.55 We will engage the Regional and District Pharmacy Councils, the regulatory authorities overseeing pharmacy and ADDO registration and monitoring, to recruit ADDO shops in each ward (ranging from ~3 to 10 per ward).

Recruitment of study participants

Study participants will be selected from three populations across study aims:

  • Aim 1:

    • Public health facilities: within catchment areas with >1 eligible public health facility, one health facility will be chosen at random, otherwise if just one public health facility exists in that catchment area, it will be recruited.

    • ADDO shops: within selected catchment areas, we will randomly approach and invite up to eight registered ADDO shops with the aim of enrolling three to four ADDOs per catchment area; shop owners and staff aged 18 years or older will be eligible to participate. Further, shops must be willing to sell or distribute all SRH products given as part of Malkia Klabu to AGYW as well as the general population. Given randomisation is at the catchment area, all ADDOs within a catchment area will belong to the same study arm.

  • Aim 2: approximately 560–600 AGYW aged 15–24 years who reside in selected catchment areas and speak Kiswahili will be recruited using respondent-driven sampling (RDS). We will begin our initial search for participants using approximately 40 AGYW ‘seeds’, identified from referrals from the study’s Youth Advisory Boards, local schools, youth organisations (including for out-of-school AGYW) and participating ADDO shops, with one per catchment area. The initial seed will receive brief training from study staff in peer recruitment before being given up to three coupons to distribute to eligible AGYW in their network. This process will be repeated in until we have reached our recruitment target.

  • Aim 3: we will conduct in-depth interviews (IDIs) with the following groups:

    • Referral public health facility staff: approximately 8–12 female referral facility staff total aged 18 years or older from participating referral public health facilities in the intervention arm will be recruited for IDIs at study endline.

    • ADDO shopkeepers: up to 30 ADDO shop owners and staff among participating ADDO shops in the intervention areas will be recruited for IDIs at study endline.

Aim 3 will also include quantitative surveys among shopkeepers already recruited in aim 1, as well as mystery client visits (further described below) which will not entail any participant recruitment.


The primary endpoints for the study are as follows (table 1):

  1. Cumulative number of HIV-positive diagnoses among AGYW aged 15–24 years over the 24-month study period.

  2. Cumulative number of ANC registrations among AGYW aged 15–24 years over the 24-month study period.

Table 1

Overview of primary and secondary outcomes and data sources to be collected among all shops (intervention and control)

These data will be abstracted from routinely collected health facility data and aggregated to the catchment (synonymous with ward) area level. Our team will abstract from the study-affiliated (ie, referral) health facility and from nearby facilities within the same catchment area. Abstraction will occur annually.

The secondary outcomes, data source and observation period are outlined in table 1.

Data collection

Aim 1

Data for the primary and secondary outcomes will be abstracted from health facility-level records annually and will include aggregate data about: number and outcomes of HIV tests by AGYW, ANC registrations by AGYW, ART initiations by AGYW (aim 2) at baseline, 12 and 24 months, reported by age groups 15–19 and 20–24 years.

Aim 2

HIVST kits and contraception distribution will be tracked in Maisha Meds over the 24-month study period. To measure programme exposure, HIV testing and unmet need for contraception, bilingual (Kiswahili and English) study staff will survey 560–600 AGYW (n=280–300 per region) at study endline. Survey topics will include demographic characteristics, exposure to Malkia Klabu (if any), recent HIV testing, contraceptive use, relationship to the referring participant (eg, friend, relative) and the size of their social network to facilitate the RDS analysis.56 57

We will conduct two rounds of four focus group discussions with AGYW who are registered Malkia Klabu members (n=4 each at 12- and 24-months) with diverse, purposefully selected AGYW (eg, various ages, in and out of school) who will elicit AGYW-level and community-level perceptions of Malkia Klabu over time and contextualise the pathways of potential impact on HIV and unintended pregnancy as suggested in the pilot findings,48 including integration with organic behaviours (eg, visiting ADDOs at the behest of others), the motivational effect of behavioural economics constructs (eg, rewards) and acceptability to community members.

Aim 3

To understand supply-side and implementation heterogeneity factors that may affect study outcomes, further described in online supplemental table 1, we will conduct (1) IDIs with ADDO staff; (2) quantitative interviews with ADDOs at baseline, midline and endline (topics outlined in online supplemental table 1); (3) IDIs with referral facility staff and (4) mystery client visits made by study-trained actors to intervention arm participating shops. Additional details about aim 3 data collection methods and measures are in online supplemental appendix 3.

Supplemental material

Supplemental material

Sample size

The trial is powered for the primary (aim 1) outcome of cumulative HIV-positive diagnoses among AGYW at 24 months based on facility records of HIV testing by AGYW aggregated to the catchment area. Using publicly available data from 2019 on HIV testing from Shinyanga and Mwanza Regions, along with estimates of HIV prevalence among AGYW (2.1%),58 we estimate a mean of 40 HIV diagnoses (SD=20.9) among AGYW over 24 months in each comparison (control) catchment area. With 40 health facility catchment areas, we will have ≥80% power to detect an increase in mean AGYW HIV diagnoses of ≥18.5 (eg, minimum detectable effect, rate ratio ≥1.46). This 46% increase in AGYW diagnoses is equivalent to the identification of less than one AGYW living with HIV per catchment area per month during the 24-month study period.

Overall, we anticipate that the analysis for the trial will include 1970 HIV test results among AGYW abstracted from referral facility records across all catchment areas. If the prevalence of HIV among AGYW is lower than expected in the comparison group (eg, 1.5%), we are adequately powered at 80% to detect a difference of 13.2 or greater in mean AGYW HIV diagnoses in the intervention arm compared with the control arm over the 24-month period. Likewise, if prevalence of HIV among AGYW is higher than expected in the comparison group (eg, 2.7%), we are adequately powered at 80% to detect increases of 23.7 or greater in mean AGYW HIV diagnoses.

Statistical analysis

We will conduct an intent-to-treat analysis to estimate the intervention’s effect on cumulative HIV-positive diagnoses and ANC registrations among AGYW (aim 1). For each outcome, we will specify a generalised linear regression model (specifying the Poisson family, log link and robust variance estimator): ln[Yi]=β01x12x2j, where Yi is the cumulative number of positive HIV tests or ANC registrations among AGYW in each catchment area i, and x1 represents area assignment to the intervention (x1=1) or comparison (x1=0) group. The model will also control for region, the stratification factor that was used in the randomisation. β1 is the effect estimate of interest: the log rate ratio of HIV diagnoses (or ANC registrations) among AGYW in intervention versus comparison catchment areas (x2 and ζj are the stratification variable and the error term, respectively). We will conduct a permutation test based on residuals from the model as proposed by Gail et al59 which has been shown to perform well in simulation studies to test the null hypothesis of no treatment effect.60 Per Consolidated Standards of Reporting Trials,61 we will report unadjusted and adjusted estimates. Sensitivity analyses assessing effect measure modification or confounding by age will be conducted.

For our aim 2 outcomes, we will use a Poisson model to estimate a rate ratio for the rate of HIVST kits and contraceptives distributed to AGYW over the 24-month study period, controlling for region as the stratification factor and accounting for catchment-level clustering. Using a log binomial model to compute a prevalence ratio, we will also assess effects on recent HIV testing, recent pregnancy testing, programme exposure and unmet need for contraception with the same model specifications for stratification and clustering, as well as the permutation test. We will use the same model specifications for aim 1 to estimate the impact on ART initiations.

For the aim 3 implementation study, we will use an open-coding approach,62 63 based on Proctor’s implementation indicators, to assess ways in which AGYW-level, shop-level, facility-level and community-level factors facilitate or hinder uptake, fidelity, scalability and sustainability.64 65 Data analysis will be iterative, allowing new themes to emerge.66 Data will be independently coded by two team members using Dedoose software.67 Qualitative and quantitative data will be triangulated to describe supply-side innovations and challenges and define relatively high-fidelity and low-fidelity models for the degree to which each shop implemented Malkia Klabu as intended.


Recruitment of catchment areas and ADDOs will take place on a rolling basis by region between May and October 2022; recruitment of AGYW will not occur until September 2024. Intervention activities will launch from July to November 2022 and the intervention will run for 24 months, with data collection points at 0, 12 and 24 months for the ADDOs and 24 months for the AGYW (online supplemental table 2). Outcome assessments measured via chart abstraction will be collected 12- and 24-months post-launch and entered into REDCap-enabled tablets.

Data management plans

Every effort will be taken to protect the confidentiality of participants. Our study team will ensure proper and secure storage of all paper forms (eg, consent forms) upon transfer from the interview site or shop to the study offices in a locked cabinet, which only designated staff members will have access to for data entry. Survey data will be collected during the interview on a tablet computer and automatically uploaded into the secure REDCap cloud-based survey platform.

We will retain the study data for up to 10 years after it is complete. At the completion of data cleaning and the primary analysis, we will prepare anonymised datasets. Only the study principal investigators (PIs), co-investigators and designated study members will have access to the data.

Ethics and dissemination

This study has been approved by the National Institutes of Health (NIH), the University of California, San Francisco Institutional Review Board (IRB) and Tanzania’s National Institute of Medical Research (NIMR). The study has convened a Data Safety and Monitoring Board that meets biannually with experts in HIV and adolescent health, and includes representatives from East Africa. Further, the study has convened three regional (given geography, despite two study regions) Youth Advisory Boards with 15–25 AGYW members in each to provide regular feedback on study progress and provide concerns and perspectives related to AGYW SRH.

Any proposed protocol changes will be submitted to US-based and Tanzania-based IRBs and will undergo standard review and approval processes and approval at each institute before proposed changes can be implemented.

The implementing partner is Health for a Prosperous Nation (HPON), a Tanzanian-based non-profit research organisation and the same organisation which carried out the pilot study. All HPON staff will be trained in and have experience with collecting sensitive information and the importance of protecting participants’ confidentiality. Study staff are required to sign a confidentiality agreement ensuring that they will not share participant data. All staff based in Tanzania who will seek informed consent from study participants are fluent in English and Kiswahili, trained in protection of human subjects in research and are experienced in obtaining informed consent. As part of the informed consent process, the research staff will verbally communicate with the participants to ensure that they understand the nature and purpose of the research, their anticipated involvement, the potential risks and benefits to participation, and the voluntary nature of their involvement. Consent forms will be read aloud to potential participants unless individuals insist that they are comfortable reading the form themselves. Potential participants who are willing to provide written informed consent will be invited to enrol in the study. For participants under age 18 years, we requested and received a waiver of parental consent given that Tanzanian law allows minors to independently consent for HIV and SRH treatment. Study participants will have contact information for NIMR and the study PIs on the consent form, a copy of which they will be given, to report adverse events.

Study findings will be disseminated in line with both the NIH data dissemination policy and the National Clinical Trials policy of the USA, including annual updates to the Clinical Trials website, as well as at conferences and in peer-reviewed journals. Local dissemination will include presentations to the local Youth Advisory Boards, the local Regional Medical Offices of Mwanza and Shinyanga, and our stakeholders and partners at the Ministry of Health. Upon conclusion of the study and primary analyses, data will be made available to outside investigators upon reasonable request and with a detailed concept proposal.

Patient and public involvement

Our study involves both AGYW, small drug shops, and regional medical and pharmacy leadership in the development and design of our trial as detailed in the Intervention design, theoretical foundation and pilot study section. Further, our study has convened three regional Youth Advisory Boards to provide feedback and input on study launch, the development of study tools and the eventual interpretation of study results; they will convene regularly until study results are finalised and disseminated.

Provisions for post-trial care

There are no anticipated harms or compensation for trial participation. There are no plans for any post-trial care.


Innovative interventions are urgently needed to reduce the disproportionate risk of HIV acquisition and unplanned pregnancy among AGYW in East Africa. Previous community-based studies have focused on community health centres to improve adolescent access and individual behavioural factors, using community-based peer navigators and extensive educational programmes to reach AGYW.57 This study builds upon this body of work by integrating drug shops as providers of SRH care and education while still partnering with community health centres in a differentiated model of care. Our study combines concepts from a comprehensive, youth-focused, HCD process,47 an integrated conceptual framework for behaviour change rooted in behavioural economics,46 and epidemiological methodologies to scale and evaluate the Malkia Klabu Programme. Our pilot study demonstrated strong results on HIVST kit and contraceptive distribution and referrals to care among AGYW.48 If proven efficacious at scale, we will have demonstrated that ADDO shops, which are already ubiquitous in Tanzania and provide basic health services in rural settings, can also serve as integral actors in the prevention of HIV and unplanned pregnancy for AGYW. This would simplify further scaling at a national level or transference of the intervention to beyond Tanzanian where small drug shops equipped with basic, but essential commodities (condoms, emergency contraception, etc) are equally ubiquitous, to transform health services for and reduce disparities in sexual health outcomes among AGYW.

Our study has several features purposely designed to facilitate its implementation and eventual scaling. Shopkeepers will use Maisha Meds, a point-of-sales tablet-based application to manage inventory and sales data. This technology integration will simultaneously promote small business management while facilitating data collection and tracking, and will be an essential component of future, scaled versions of Malkia Klabu, which may be used to channel essential commodities supplied by public sector programmes. Further, our study team has convened three regional Youth Advisory Boards with AGYW who regularly provide feedback on study activities, review enrolment and to provide feedback on implementation challenges throughout the study rollout; this is in direct alignment with the Quality Standards Framework for adolescent SRH interventions.58 Based on feedback from health facility staff and the pilot study Youth Advisory Board, this study will work with the enrolled health facilities to develop a comprehensive differentiated care model that involves existing peer navigators and facility counsellors. Specifically, AGYW products sold at ADDOs will contain referrals to trained peer navigators and girl-friendly providers by name who will be trained to provide next-level services (eg, HIV confirmatory testing, LARC) not offered by ADDOs. Finally, our study is a rigorous evaluation of the scaling of an HCD-derived intervention47 infused with concepts from behavioural economics that has already demonstrated preliminary effectiveness48 and has metrics tied to a clear impact pathway; there are few such evaluations.

This study is not without potential limitations. Given the primary outcome of HIV diagnoses and ANC registrations will be measured at the population level, it will be difficult to disentangle other community-wide efforts to prevent HIV and unplanned pregnancy among AGYW. At the same time, the tracking of individual HIVST kits and contraceptives/urine pregnancy tests among AGYW patrons of ADDOs would have presented a number of logistical, ethical and implementation challenges, especially at scale; measuring the outcomes at a community-level preserves anonymity and privacy of the AGYW and is in line with WHO guidelines for HIVST interventions and measurement.39 40 To account for this potential measurement challenge, we purposively enrolled catchment areas with fewer than three public health facilities and will conduct data abstraction among all health facilities within that catchment area in addition to the primary referral facility for our study. In practice, this approach excluded few catchment areas, as the two provinces from which catchment areas were drawn (Mwanza and Shinyanga) are largely rural. To complement this community-level data, we will collect shop-level interim outputs (ie, distribution of HIVST kits and contraception in intervention areas) in line with our impact pathway, allowing our study to evaluate where or how far along the hypothesised path from the intervention input to the primary effectiveness outcomes we can demonstrate efficacy. The choice to use RDS also brings some limitations, mainly in that it is a non-probability sample as well as unknowns around the network size of AGYW.68 Nevertheless, there are strengths of the RDS, including its strength in recruiting ‘hidden populations’, such as sexually active AGYW, those out of school and/or those who are young mothers, which we believe outweigh historical questions raised about RDS.

By the end of this study, we will have comprehensively evaluated an HCD-derived intervention with integration from behavioural economics to evaluate how our intervention affects HIV diagnoses and ANC registrations among AGYW in two high HIV burden regions of Tanzania via a c-RCT. We will have evaluated supply-side and demand-side innovations and challenges, as well as implementation fidelity, to understand specific mechanisms which may have been barriers or facilitators to our study’s implementation. This is novel as few evaluations of such programmes exist, and the rigorous nature of the evaluation will provide multiple points of data for potential scale-up.


We would like to acknowledge the ADDO owners, shopkeepers and clinic staff for their time and participation in this study. We thank the Tanzanian Pharmacy Council for their support for our study, as well as Elizabeth Shekalaghe specifically, the CEO of the Tanzanian Pharmacy Council. We acknowledge the regional medical officers, regional pharmacists, the Regional Health Management Teams, and the Council Health Management Teams in Mwanza and Shinyanga for their support for this study. Further, we would like to thank the members of the Youth Advisory Boards for their contributions and feedback provided throughout the study timeline. We thank our study staff for their crucial contributions to this work, including Atuganile Kalinjila, Juliet Allan, Lisa Richard, Janeth Msasa, Zaburi Morris, Moza Albert, Janeth Maliga, Joyce Maboko, Victor Brown and Frank Joseph. We thank the Data Safety and Monitoring Board members for important feedback and considerations as we prepare for study launch. We thank Lauren Hunter for her important intellectual contributions to the pilot study which influence this study.

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