Micronutrient powders (MNP), a mixture of vitamins and minerals, enclosed in single‐dose sachets that are stirred into a child's portion of food immediately before consumption, are one of the few World Health Organization (WHO) recommended nutrition interventions to address anaemia and iron deficiency in young children and improve the quality of complementary feeding of young children 6–23 months (De‐Regil, Suchdev, Vist, Walleser, & Peña‐Rosas, 2013; World Health Organization [WHO], 2016). MNP interventions have been implemented in a wide range of countries using different combinations of delivery models, platforms, and channels, illustrating their potential for MNP distribution (Reerink et al., 2017). However, there is insufficient evidence to guide effective, context‐specific delivery of the intervention in different systems, cultures, and communities (Reerink et al., 2017). More investigations to examine implementation are needed in order to understand what happened in a programme and how that could affect programme outcomes or impacts (Vossenaar et al., 2017).

In Mozambique, two third (68.7%) of children 6 months to 5 years suffer from anaemia (Ministerio da Saude [MISAU] et al., 2011). The Ministry of Health (MISAU, acronym in Portuguese) developed in 2010 a comprehensive action plan (Government of the Republic of Mozambique, 2010), detailing a policy related to a number of nutrition interventions. Within the context of counselling to improve infant and young child (IYC) feeding practices and aligned with recent WHO guidance on the use of MNP for point‐of‐use fortification of foods consumed by IYC (WHO, 2016), the government recommended the inclusion of MNP as part of the national strategy. Many development partners work closely with MISAU, and several were asked to pilot‐test the delivery of MNP across different regions of the country to inform how MNP delivery could be scaled‐up in the country.

In two districts of Sofala Province, Global Alliance for Improved Nutrition (GAIN), Save the Children (SC), and Population Services International (PSI) supported MISAU to implement a trial using a voucher distribution system. Caregivers of children aged 6–23 months were provided with IYC feeding counselling as part of ongoing MISAU and SC programmes and vouchers that could be redeemed without cost for MNP called VitaMais at vendors of PSI's existing sales platform. The logic behind the design decision was that using a market‐based platform would alleviate the burden on the public health supply system while increasing accessibility of MNP through distribution points located in communities where caregivers live. Testing the use of vouchers was also relevant to inform the feasibility of using them to subsidize MNP cost (rather than provide MNP free of cost upon redemption).

A formative process evaluation was conducted by GAIN with technical assistance from the Division of Nutrition, Physical Activity, and Obesity, Centers for Disease Control and Prevention to assess the viability of the specific model implemented in Mozambique to deliver MNP and motivate adherence to recommendations regarding its use. To illustrate how the delivery of the programme would result in continuing and appropriate use of MNP, we developed a programme impact pathway (PIP; Habicht & Pelto, 2012) through consultation with programme staff and an extensive literature review on factors affecting MNP adherence (Tumilowicz, Schnefke, Neufeld, & Pelto, 2017). The PIP is composed of two systems: (a) a programme delivery system including the processes in which the intervention is delivered to the household and (b) a household delivery system that consists of all steps needed for a child to consume a biologically impactful dose. Figure 1 presents the flow of the PIP in the form of programme component exposures and actions by the caregiver. The PIP describes the transmission of MNP and behaviour change communication (BCC) activities from the programme delivery system to the household delivery system and the sequence of activities to prepare food with MNP and feed it to the child.

We identified two main questions to be addressed in the evaluation: (a) What proportion of caregivers received the intervention and adhered to MNP recommendations, and (b) how did delivery and utilization processes affect programme outcomes, including coverage and utilization of MNP. Examination of these two questions required a complex study design and mixed methods. Therefore, we created two streams of inquiry: (a) an examination of programme outcomes using cross‐sectional survey data and (b) a focused ethnographic study (FES) to investigate delivery experiences and MNP use from perspectives of caregivers, programme managers, and implementers (Cove & Pelto, 2010; Pelto, Armar‐Klemesu, Siekmann, & Schofield, 2013). The central purpose of ethnography is to obtain the emic view—the insider's perspective—that allows for the discovery of conditions and behaviours that are not foreseen (Pelto & Pelto, 1978). The difference between ethnography and other social science methods of investigation is that ethnographers aim to discover what people do and why, then use what is learned to build theories rather than assess the validity of preconceived theories (Schensul & LeCompte, 2012). In this paper, we focus on what we unexpectedly learned through the mixed methods formative evaluation design about the delivery and redemption of vouchers and how and why programme delivery unfolded as it did primarily from the ethnographic study results.

The results of the cross‐sectional survey revealed bottlenecks in the transfer of messages, vouchers, and VitaMais between the programme delivery system to caregivers. About one third of caregivers in Beira and about four in 10 caregivers in Dondo had not heard about VitaMais (Figure 2). A small proportion of caregivers reported having received a voucher (16.8% in Beira and 6.8% in Dondo), making that step the largest programme implementation bottleneck. However, the survey also revealed that, unexpectedly, many caregivers received VitaMais through mechanisms that bypassed the voucher system (22.5% in Beira and 29.6% in Dondo). Virtually, all caregivers who received VitaMais reported ever feeding it to their child.

We had assumed that the accessibility of vouchers and VitaMais would be improved through activistas located in communities where caregivers live, but health centres were the most commonly accessed distribution point (Table 4). Among caregivers who ever heard about VitaMais, more than two‐thirds heard about it at a health centre (67.8% in Beira and 74.6% in Dondo) whereas only about one‐tenth from activistas in the community (13.4% in Beira and 5.9% in Dondo). If vouchers were received, it was more commonly from programme implementers stationed at health facilities (65.4% in Beira and 73.0% in Dondo) than activistas in the community (16.0% in Beira and 2.7% in Dondo). Only about one in four or one in five caregivers had heard of Troca Aki shops, and 4.9% in Beira and 21.6% in Dondo needed help redeeming vouchers at the Troca Aki shop. Of those interested in using VitaMais in the future, most caregivers preferred health facilities (68.8% in Beira and 79.1% in Dondo) when asked about a future location for redeeming vouchers for VitaMais, although 30–40% also named shops or the market as potential locations. The majority of caregivers who received VitaMais bypassing the voucher system received it at health facilities (54.8% in Beira and 72.2% in Dondo).

Shifting to the results of the ethnographic study, the FES data revealed the challenges encountered by caregivers with the voucher system and how and why programme implementers bypassed it to deliver VitaMais. The results are presented in five themes, which emerged from our exploration of the in‐depth interviews with caregivers, semistructured interviews with programme managers, and surveys with programme implementers.

The intention of the distribution model was to use a market‐based platform that would avoid burdening the public health supply system and increase accessibility of VitaMais for caregivers. However, this model required installing two distinct supply chains: one for vouchers and one for VitaMais. Consequently, programme implementers and caregivers had to learn about a new product and complex supply, distribution, and redemption processes. The novelty and complexity of the model contributed to programme implementers' difficulty to deliver VitaMais and caregivers' hampered efforts to obtain it, which is reflected by the fact that only one third of caregivers received VitaMais. The results suggest that caregivers' ability to obtain VitaMais was impeded by poor instruction on redemption procedures, extra time required to go to Troca Aki shops, and stock‐outs. Fortunately, dedicated and resourceful programme implementers developed strategies to overcome many implementation challenges, primarily through eliminating the need for caregivers to use vouchers. Notably, caregivers reported motivation for redeeming vouchers and using VitaMais, and most caregivers who received VitaMais fed it to their child. The finding that mothers are motivated to try MNP is consistent with other studies across a range of contexts, for example, Vietnam (Nguyen et al., 2016), Ghana (Aaron et al., 2016), and Ethiopia (Tumilowicz et al., 2019). This suggests that programmes are generally effective in motivating initial use, and more attention is required to improve access to MNP and support continued use.

The results of this formative evaluation can inform MNP programme delivery systems in Mozambique and other contexts more broadly, particularly in terms of the challenges of ensuring that caregivers learn about MNP and easily obtain it. MNP have most commonly been distributed through the health sector free of charge as part of IYC feeding programmes (Reerink et al., 2017). Increasingly fee‐based models are being considered with the intention of lowering intervention costs and building sustainability. Fee‐based models, which reduce or eliminate public sector cost of procuring and distributing MNP, have obvious financial benefits for public health budgets. However, they transfer economic and noneconomic costs to caregivers. To partially mitigate, these costs require careful attention to design and develop efficient and reliable supply chains and convenient distribution locations. The nutrition community can find some models for doing this in other public health sectors, such as reproductive health and malaria prevention where applied marketing principles and techniques have been used to promote public health interventions involving sales and uptake of products (Firestone, Rowe, Modi, & Sievers, 2017).

Caregivers' preference for receiving VitaMais at health centres may be the consequence of their difficulty with voucher redemption and inadequate coverage of activistas. On the other hand, despite low coverage of activistas, for some of the population, they played a key role in obtaining VitaMais for caregivers and carrying out BCC activities. In Mozambique, as in many other places, the frontline worker is a minimally paid community member or volunteer. In recent systematic reviews, frontline workers in communities played a central role in ensuring caregivers received MNP (Reerink et al., 2017), and their knowledge and skill were frequently cited as critical for adherence (Tumilowicz et al., 2017). Moreover, MNP distribution through frontline workers in the community compared with health centres may be conditionally more cost‐effective for achieving higher coverage and adherence outcomes, as was recently demonstrated in Uganda (Baker & Vosti, 2018).

Over the last 15 years, MISAU signed codes of conduct for unpaid, volunteer activistas with donor agencies and non‐governmental organizations (Ministerio da Saude [MISAU], 2000, 2005) and revitalized its paid community health worker programme (MISAU, 2010). However, both activistas and community health workers in Mozambique still face challenges in carrying out their activities (Ndima et al., 2015). Many activistas interviewed for this study stated that they faced financial difficulties and requested payment for their services. Considering the low overall voucher and VitaMais coverage and ingenuity of activistas to overcome barriers with the distribution system demonstrated in this evaluation, there may be a critical role and potential for frontline workers in Mozambique to undertake health and nutrition promotion activities. However, more support is likely required to sustain their work.

Mozambique's public health supply chain frequently suffers stock‐outs of essential medicines (Salomão, Sacarlal, & Gudo, 2017), as do other resource‐constrained systems (Mukasa, Ali, Farron, & Van de Weerdt, 2017). The delivery of VitaMais during this short project (15 months) aimed to alleviate the burden of adding another product to this system by using vouchers redeemable through a market‐based platform. Other countries have shown success with similar arrangements to deliver health products, such as insecticide‐treated nets for malaria prevention in Tanzania (Kramer et al., 2017). In addition to overcoming supply chain constraints, vouchers are also a means to subsidize health goods and services (Brody, Bellows, Campbell, & Potts, 2013). Although the VitaMais voucher system faced difficulties, voucher programmes have shown promise in other contexts where the investment and willingness to make necessary adjustments based on initial challenges can be ensured. The Tanzania National Voucher Scheme required years and considerable course corrections to programme design to achieve high coverage (Kramer et al., 2017). For example, if further assessment shows that the benefits of not using the public health supply system outweigh the costs of sustaining it, activistas could continue to redeem vouchers for caregivers or the role of the Troca Aki shop could be changed to supply the health centre rather than the caregiver directly. Programmes need time and resources to apply lessons learned and iterative improvement processes to take place.

In retrospect, we see that the study could have been strengthened by sequencing the cross‐sectional survey and FES rather than conducting them simultaneously. Had the cross‐sectional survey results been available before designing the FES, it would have been possible to more fully explore the population's response to the voucher system and the motivations of programme implementers in their activities to circumvent direct household voucher redemption. For example, we do not have sufficient evidence to more fully explore how demand (in addition to supply) for the product facilitated or inhibited voucher redemption. Conversely, carrying out the FES before the cross‐sectional survey could have allowed for quantitative assessment of the frequency of behaviours and circumstances uncovered in the caregiver narratives. The sampling approach of caregivers interviewed as part of the FES, selecting only caregivers who had received vouchers or VitaMais, also limited data collection about why one third of caregivers never heard about the programme.

Using an ethnographic, mixed methods approach in the formative evaluation allowed us to explore unexpected programme outcomes and triangulate findings. Ethnographic methods resulted in key learning about caregiver's attempts to redeem vouchers and how the programme design can be improved. It is still rare in implementation research in nutrition to find evaluations of MNP programmes or international nutrition programmes more broadly, using ethnography to study population responses to interventions (Tumilowicz et al., 2017; Tumilowicz, Neufeld, & Pelto, 2015). We hope this example will encourage others to make use of this powerful tool and the value of mixed methods designs to build knowledge for programme improvement.

The authors declare that they have no conflicts of interest.

AT, EP, MEJ, GHP, and LMN designed the study. KK, JV, and EP supervised data collection. AT, MV, KK, JV, GHP, EP, WG, and AN conducted data analysis. All authors participated in the interpretation of results. AT and MV wrote the manuscript. All authors read, revised, and approved the final version submitted for publication.