Small quantity lipid-based nutritional supplementation and measles vaccination coverage in children aged 6−23 months: a pragmatic cluster

Abstract Undernutrition and infectious diseases pose a double threat to child survival, especially in areas with a high malnutrition burden and low vaccination coverage. In this study, we evaluated whether distributing preventive small-quantity lipid-based nutrient supplements (SQ-LNS) alongside routine immunization services may increase vaccine uptake in a pediatric, pragmatic, cluster-randomized controlled trial in northern Nigeria. Twenty geographically defined clusters across two Local Government Areas were randomized 1:1 to the NutriVax strategy (intervention) or standard National Program of Immunization (NPI) services (control). NutriVax provided a monthly ration of SQ-LNS to children aged 6−23 months after routine NPI delivery at primary healthcare centers. The primary outcome was coverage of the first dose of measles-containing vaccine (MCV1) verified by vaccination card among children aged 12−23 months, assessed in an endline population-based household cross-sectional survey 12 months after conducting a similar baseline survey. The endline survey included 1,604 children (801 control, 803 NutriVax); 48% of children surveyed in intervention clusters had ever received SQ-LNS. The odds of receiving card-verified MCV1 were two times higher in the NutriVax arm than in the control arm (odds ratio = 2.08, 95% confidence interval (CI): 1.30−3.35, P = 0.004). The difference-in-differences, cluster conditional analysis indicated a 20.1 percentage-point (pp) increase in MCV1 coverage from baseline (95% CI: 13.7−26.5 pp, P < 0.0001) relative to the control arm. Co-delivering SQ-LNS with routine immunization substantially improved card-verified MCV1 uptake, supporting a scalable strategy to make progress toward targets set by the World Health Organizationʼs Immunization Agenda 2030 in similar settings. ClinicalTrials.gov identifier: NCT06387511. Main Undernutrition and infectious diseases form a vicious cycle, especially in settings where vaccination coverage is low, posing a double threat to child survival. Infections predispose children to undernutrition by reducing dietary intake, impairing nutrient absorption and increasing metabolic demands, while undernutrition, including underweight, wasting and stunting, weakens immune function and heightens susceptibility to infections as well as their severity1. This dynamic is a leading contributor to mortality in children younger than 5 years of age worldwide, particularly in sub-Saharan Africa2. The World Health Organization’s (WHO) Expanded Program on Immunization has been the greatest driver of child survival over the past 50 years, averting an estimated 146 million deaths among children younger than 5 years and accounting for approximately 40% of the global decline in infant mortality—more than half of which occurred in Africa3. Measles vaccination has contributed most to this impact, preventing an estimated 92 million deaths3. Despite these gains, measles remains a major public health threat. Its high transmissibility requires at least 95% immunization coverage with two timely doses to achieve herd immunity, a target that remains unmet in many settings4. In 2023, global measles cases increased to an estimated 10.3 million, resulting in more than 100,000 deaths, predominantly among children in Africa5. At the same time, 15.7 million children globally were classified as zero-dose—children who have not received the preliminary dose of a diphtheria−tetanus−pertussis-containing or pentavalent vaccine—highlighting persistent and profound inequities in access to routine immunization services6. In sub-Saharan Africa, childhood vaccination is limited by a wide array of factors, including caregiver availability, low or distorted vaccine knowledge, service shortages, access barriers, parental education, household wealth and rural residence, highlighting the complex socioeconomic and health system context shaping immunization behaviors7,8. Evidence on interventions to improve childhood vaccine coverage in low- and middle-income countries is mixed and context dependent. A 2023 Cochrane Systematic Review reported little effect of health education, SMS reminders or financial incentives; but the only study included in the review using a food-based incentive did show a significant increase in coverage9. Integrated delivery of essential nutrition interventions and routine immunizations has been a strategic area in global child health for decades, but a recent scoping review found that, to date, the only approach implemented at scale has been vitamin A supplementation delivered with routine vaccines. Effective integration of immunization and nutrition activities requires alignment of target populations, timing of service delivery, acceptability to caregivers and similar competency requirements for health personnel10. Delivering SQ-LNS with routine immunization meets these criteria, and modeling suggests that such a strategy could substantially reduce measles morbidity and mortality11. SQ-LNS is a highly nutrient-dense, food-based supplement designed for the prevention of malnutrition in children 6−23 months of age, and daily supplementation with a single 20-g sachet for up to 12 months has been demonstrated to reduce the risk of all-cause mortality12, iron deficiency anemia13, severe wasting and severe stunting14 and developmental delays15. The recent WHO Guideline for complementary feeding in children 6−23 months recommends SQ-LNS in certain food-insecure contexts, with high-certainty evidence16. SQ-LNS has also been included in recommendations for nutrition-specific interventions to optimize health and growth17 but is rarely provided due to inadequate international and domestic financing. Beyond nutritional benefits, free provision of SQ-LNS at primary healthcare facilities at the end of the vaccine circuit may encourage caregiver attendance, thus creating additional opportunities for vaccination and helping overcome previously identified barriers such as distance, distrust and vaccine hesitancy. Nigeria is an epicenter of this undernutrition−infectious disease cycle. Globally, it is among the nations with the highest numbers of under-5 deaths associated with undernutrition2, measles cases and outbreaks5,18 and zero-dose children6. These intersecting challenges, particularly in conflict-affected northern Nigeria where health service delivery is particularly fragile, contribute to a national under-5 mortality rate of 105 per 1,000 live births, which is far above the Sustainable Development Goals target of 25 per 1,000 by 2030 (ref. 19). We conducted an open-label pediatric, pragmatic, superiority, two-arm, parallel, cluster-randomized controlled trial with baseline measurements in northern Nigeria to assess whether co-delivering SQ-LNS to children aged 6−23 months with the routine NPI—the NutriVax strategy—at primary healthcare centers (PHCCs) could increase vaccine uptake compared to routine NPI alone. The primary objective was to assess card-verified coverage of MCV1 among children aged 12−23 months after 10 months of intervention implementation. Secondary objectives were to assess the effects of the NutriVax strategy on coverage of other childhood vaccines compared to NPI alone. Primary and secondary outcomes were measured using a population-based household endline cross-sectional survey conducted 12 months after completion of a similar baseline survey, which was conducted before implementation of the intervention. Although children aged 6−23 months were eligible for SQ-LNS distribution, in line with WHO Guidelines16 and Nigeria’s national action plan for nutrition20, the population-based household surveys used to assess the primary and secondary objectives included children aged 12−23 months, in accordance with the WHO manual for population-based vaccination coverage surveys of vaccines recommended before 12 months of age21. Results Study design and setting This study was conducted in Nguru and Karasuwa Local Government Areas in Yobe State, Nigeria, characterized in 2022 by low card-verified MCV coverage of 29.9% in children aged 12−23 months and high global acute malnutrition prevalence of 14.2% in children aged 6−59 months, including 3.7% prevalence of severe acute malnutrition22. Each Local Government Area comprised 10 clusters defined as geographically and administratively distinct health areas. Details on estimated population from the Ministry of Health (MoH) by Local Government Areas and by clusters and proportion served by type of health facilities are presented in Extended Data Table 1. At the time of the study, there had never been any SQ-LNS distribution program in the Local Government Areas nor were there any MoH plans to do so. Their catchment populations were served by one PHCC per cluster. In all clusters, the NPI was routinely available and followed a standardized vaccination schedule (Extended Data Table 2), with no reported vaccine stockouts during the study period. A total of 20 clusters were randomly assigned in a 1:1 ratio, stratified by Local Government Area, to the control arm (NPI alone) or to the NutriVax arm (NPI plus SQ-LNS distribution). Standardized sensitization sessions were conducted both at PHCCs and within communities throughout the study period to promote (1) vaccination and infant and young child feeding in both arms and (2) SQ-LNS eligibility and proper use in the NutriVax arm only. Characteristics of clusters and survey participants All clusters were included in the analyses (Fig. 1). Household cross-sectional surveys were conducted from 9−26 May 2024 (baseline) and from 12−31 May 2025 (endline). At baseline, 1,597 children aged 12−23 months were included (796 control, 801 NutriVax), and 1,604 were included at endline (801 control, 803 NutriVax), with an average cluster size of 80 participants at both timepoints (Fig. 1). Participation rates were higher than 99.5% at both baseline and endline with minimal household refusals (n = 5 and n = 2 at baseline and endline, respectively), and the sample in each survey represented approximately 12% of the total population of children aged 12−23 months across all clusters (Table 1). Baseline characteristics of clusters and participants were generally well balanced between the control and NutriVax arms (Table 1 and Supplementary Table 1), across Local Government Areas (Supplementary Table 2) and by sex (Supplementary Table 3). Household and caregiver characteristics, such as maternal age, education and household composition, were similar across arms; vaccination card retention, however, was higher in the control arm (384 children, 48%) than in the NutriVax arm (318 children, 40%). In the NutriVax arm, caregivers of children aged 6−22 months attending PHCCs received a monthly SQ-LNS supply (one sachet per day), extended to 3 months in hard-to-reach areas (that is, those living more than 10 km from the PHCC), until children reached 23 months of age or completed 12 months of supplementation. Participation in the SQ-LNS program was voluntary, and caregivers could receive SQ-LNS regardless of whether scheduled vaccines were accepted. Between July 2024 and July 2025, SQ-LNS distribution across the 10 PHCCs in NutriVax clusters reached 19,739 children and delivered 3,753,009 sachets (Extended Data Table 3). At endline, 386 of 803 children (48%) and 33 of 801 children (4%) had ever received SQ-LNS at PHCCs in the NutriVax and control arms, respectively (Table 1); SQ-LNS uptake in NutriVax arm ranged from 30% to 71% across clusters (Extended Data Table 4). Primary outcome At baseline, the proportion of children who had received MCV1 verified on a vaccination card was 29.9% and 25.0% in the control and NutriVax arms, respectively (Table 2), driven by higher coverage in Karasuwa Local Government Area (32.9% in the control arm) compared to other groups (Extended Data Table 5). Stratification by sex at baseline did not reveal notable differences in vaccination card possession or MCV1 coverage (Extended Data Table 6). Among respondents declaring incomplete vaccination, the most common reasons cited were maternal workload (reported by approximately 25% of caregivers) and fear of side effects, family-related issues or long distance to immunization sites; each of these latter three reasons was reported by approximately 16% of respondents in both arms (Table 1). At endline, MCV1 coverage verified by card increased to 41.2% and 55.3% in the control and NutriVax arms, respectively (Table 2). The crude absolute difference in MCV1 coverage between baseline and endline was 11.3 pp in control clusters (ranging from −16.3 pp to 33.8 pp) and 30.3 pp in NutriVax clusters (ranging from 11.4 pp to 53.5 pp) (Extended Data Table 7). The cluster-specific odds ratio (OR) estimated by the primary mixed-effects logistic regression model was 2.08 (95% CI: 1.30−3.35, P = 0.004; Fig. 2), and difference-in-differences (DiD), cluster conditional analysis yielded an OR of 2.39 (95% CI: 1.76−3.25, P < 0.0001; Table 3), indicating that, among children from the same ward, exposure to the NutriVax strategy more than doubled the odds of receiving card-verified MCV1 when compared to the control arm. Prespecified and post hoc sensitivity analyses produced consistent results (Fig. 2). Post hoc marginal-level analyses corroborated these findings across both modeling approaches, with ORs ranging from 2.04 (95% CI: 1.30−3.16, P = 0.0008; Extended Data Table 8) to 2.30 (95% CI: 1.71−3.09, P < 0.0001; Extended Data Table 9) in the mixed-effects logistic regression and DiD analyses, respectively. Overall, the DiD, cluster conditional analysis indicated that the NutriVax strategy increased card-verified MCV1 coverage by 20.1 pp (95% CI: 13.7−26.5 pp, P < 0.0001; Table 3) from baseline relative to the control arm. The distribution of cluster-specific MCV1 coverage increased from a median of 26.2% at baseline (interquartile range (IQR): 17.2−33.9%; range 11.0−57.5%) to 46.9% (IQR: 36.2−56.2%; range 23.8−79.8%), based on Extended Data Table 7, at endline. The latent-scale and observed intracluster correlation coefficients (ICCs) for MCV1 at endline were 0.106 and 0.089 overall, respectively (0.069 and 0.062 in the control arm and 0.098 and 0.085 in the NutriVax arm), indicating modest but non-negligible clustering at the ward level. The latent ICC is defined on the logistic scale, whereas the observed ICC is defined on the outcome probability scale (Extended Data Table 10). Secondary outcomes Secondary outcomes at endline were consistently more favorable in the NutriVax arm than in the control arm (Table 2). Cluster-level analyses (Fig. 2) indicated that the NutriVax strategy significantly improved the timeliness of card-verified MCV1 (OR = 1.78, 95% CI: 1.10−2.91, P = 0.0312) and doubled the odds of having a vaccination card (OR = 2.09, 95% CI: 1.36−3.23, P = 0.0114) and of receiving card-verified pentavalent 3 (OR = 2.16, 95% CI: 1.38−3.41, P = 0.0114) and meningitis (OR = 2.00, 95% CI: 1.26−3.21, P = 0.0205) vaccines while halving the odds of being card-verified zero-dose (OR = 0.50, 95% CI: 0.33−0.75, P = 0.0104). Based on vaccination card data or caregiver recall, the NutriVax strategy doubled the odds of receiving yellow fever vaccine (OR = 2.04, 95% CI: 1.26−3.33, P = 0.0205), significantly decreased the odds of being simultaneously zero-dose and acutely malnourished (OR = 0.30, 95% CI: 0.13−0.72, P = 0.021) and increased the odds of having ever received a dose of vitamin A (OR = 1.82, 95% CI: 1.12–2.96, P = 0.0295). Marginal estimates were consistent with cluster-level findings (Extended Data Tables 8 and 9). The NutriVax strategy also doubled the odds of receiving card-verified MCV2 in both cluster and post hoc marginal analyses with the DiD approach (cluster OR = 2.14, 95% CI: 1.34−3.46, P < 0.0001; Table 3; marginal OR = 2.11, 95% CI: 1.33−3.42, P = 0.0016; Extended Data Table 9) among children aged 15 months or older and significantly increased the odds of being fully vaccinated (Table 3 and Extended Data Table 9). As shown in Table 3, NutriVax significantly increased the probabilities of retaining a vaccination card by 17.8 pp (95% CI: 11.0−24.3 pp, P < 0.0001), of receiving the third dose of card-verified pentavalent vaccine by 20.4 pp (95% CI: 13.6−26.8 pp, P < 0.0001), of receiving card-verified meningitis vaccine by 20.0 pp (95% CI: 13.4−26.3 pp, P < 0.0001), of timeliness of MCV2 among children 15 months or older by 7.1 pp (95% CI: 1.2−12.8 pp, P = 0.0168), of being fully vaccinated by 9.9 pp (95% CI: 3.9−16.0 pp, P = 0.0016) and of having ever received a dose of vitamin A by 13.6 pp (95% CI: 7.0−20.1 pp, P = 0.0004) while reducing zero-dose prevalence by 17.0 pp (95% CI: −23.7 to −10.5 pp, P < 0.0001). The mean DiD obtained from the parametric bootstrap was numerically very similar to the DiD based on model-predicted probabilities (Supplementary Table 4). At endline, Table 1 shows that maternal workload remained the major barrier for children not being fully vaccinated in both arms. The fear of vaccine side effects declined in both arms between baseline and endline, and lack of confidence in immunization was halved in the NutriVax arm only. However, long waiting times were more frequently reported as a barrier to vaccination in the NutriVax clusters. Safety and adverse events No adverse events were reported as being related to the co-delivery of SQ-LNS with routine immunization. Hospitalization in the 3 months preceding the surveys was reported for 2% of children both at baseline, before implementation of the intervention, and at endline, 10 months after the intervention was implemented. Reported morbidity decreased from 12% at baseline to 3% at endline in the NutriVax arm and from 13% to 5% in the control arm (Table 1). Post hoc exploratory non-randomized analysis of outcomes stratified by SQ-LNS uptake Within the NutriVax clusters, children who received SQ-LNS had generally similar sociodemographic and clinical characteristics to those who did not but lived slightly closer to PHCCs. Caregivers of children who did not receive SQ-LNS more frequently reported maternal workload as the main barrier for their child not being fully vaccinated (Supplementary Table 5). Supplementary Table 6 presents an exploratory, non-randomized, post hoc analysis comparing children who had ever received SQ-LNS to those who had not. Card-verified MCV1 coverage was substantially higher among children who received SQ-LNS (73.3% versus 38.6%), with similar trends observed for MCV2, pentavalent 3, meningitis and yellow fever vaccination. Likewise, the prevalence of zero-dose status by card or recall was dramatically lower among children who received SQ-LNS compared to those who did not (7.3% versus 29.5%, respectively). Discussion This study demonstrates that distributing SQ-LNS alongside routine immunizations at PHCCs substantially improved vaccination outcomes among children aged 12−23 months. The odds of receiving card-verified MCV1 were two times higher for children in the NutriVax arm compared to those in the control arm, translating into a 20-pp absolute increase compared to routine NPI. Benefits were observed consistently at both the cluster and population levels, with substantial improvements in vaccine card retention; in coverage of MCV1, MCV2, pentavalent 3, meningitis and yellow fever vaccines, both card verified or by recall; and in timeliness of MCV1 vaccination. NutriVax also greatly reduced the proportion of children who were zero-dose as well as a highly vulnerable subgroup of children who were simultaneously zero-dose and acutely malnourished, addressing at the same time two key drivers of childhood morbidity and mortality. The significant difference in vitamin A supplementation suggests that SQ-LNS also led to increased uptake of other essential child health interventions. All of this was accomplished in a pragmatic program setting with 48% of SQ-LNS coverage at the population level. Although there is strong evidence for the impact of SQ-LNS on child growth, it was not available in the study area at the time of the trial. Previous evidence on nutrition support to increase immunization is limited. Another cluster-randomized trial in rural Rajasthan, India, found that providing a small amount of family food (1 kg of raw lentils per immunization administered) significantly increased the likelihood of children being fully immunized23. A recent meta-analysis indicated that other interventions, such as reminders or cash incentives, can modestly increase MCV1 coverage—relative risk = 1.19, 95% CI: 1.05−1.36 and relative risk = 1.19, 95% CI: 1.00−1.28, respectively—although effects are variable and context specific24. An earlier cluster-randomized trial in northern Nigeria showed a 14.1-pp difference (95% CI: 10−18 pp; P < 0.01) in MCV1 coverage by recall only relative to control with a cash incentive program that is already scaled-up in many parts of northern Nigeria25. The impact of a 20-pp increase in coverage on reducing measles incidence and mortality is not yet known. Modeling based on data from Niger has shown that an increase in already high measles vaccination coverage areas (from 75% to 85%), combined with the benefits of increased coverage for treatment of wasting and mass nutritional supplementation for nutritionally at-risk population, contributes to sizeable reductions in measles incidence and mortality11. Future work will include updating this model to reflect the nutrition and measles transmission context in Yobe State, which accounted for 11% of Nigeriaʼs 19,213 confirmed measles cases from January to November 2025 (ref. 26). Although we report substantial gains in MCV1 coverage in the NutriVax arm, it is important to note that endline coverage by card (55.3%) or by card or recall (68.5%) was still well below the 95% immunization coverage needed to achieve herd immunity. Even though promising, solely associating SQ-LNS with routine immunizations in health centers would be insufficient to achieve the recommended vaccination coverage at population level in an environment as challenging as northern Nigeria. Decentralizing SQ-LNS distributions to lower-level health posts, however, and not just PHCCs as in this trial, would likely further increase SQ-LNS uptake as well as MCV1 coverage, as suggested by the exploratory, post hoc analysis (Supplementary Table 6). Many countries like Nigeria use mass vaccination campaigns and other supplemental immunization activities (SIAs) to achieve temporarily high coverage but at substantial costs in terms of financial and human resources27. NutriVax would not eliminate the need for SIAs, but, if it contributed to steady gains in coverage in the routine immunization program, it could reduce their frequency and scale. Completing two doses of measles vaccine in a timely fashion remains a persistent challenge globally. In our trial, baseline timeliness of MCV1 among children aged 12−23 months and coverage by card of MCV2 among children aged 15−23 months were low (17% and 12%, respectively). In Nigeria and elsewhere, substantial dropout between MCV1 and MCV2 has been documented in a pooled analysis of surveys28. Conversely, these analyses showed that receiving MCV1 before 12 months of age was positively associated with MCV2 uptake. Our DiD analysis showed that NutriVax significantly increased the timeliness of MCV1 and coverage of both MCV1 and MCV2. Although endline coverage of card-verified MCV2 in the NutriVax arm remained low (27.6%), it highlights the potential for making progress toward reaching targets for achieving the two doses on the schedule set out by the WHO4. Beyond the impact on age-eligible immunizations, our study demonstrated how SQ-LNS supplementation can also identify and catch-up children who missed some of their routine infant immunizations. A major goal of the WHO Immunization Agenda 2030 is to halve the number of zero-dose children by 2030 (ref. 4). Although substantial efforts are ongoing to reach zero-dose children29, particularly in Nigeria30, and catch-up children who have not received their essential immunizations, there is a dearth of systematic and robust evidence on what successful zero-dose interventions can be deployed through the routine immunization system31. NutriVax halved the odds of being zero-dose by card or recall, meeting the WHO target, and translating into a 12.5-pp reduction in the zero-dose population compared to the control arm. Cluster-specific variability of MCV1 coverage was observed at both baseline and endline, reflecting the context-specific barriers faced by caregivers in accessing immunization services more broadly in sub-Saharan Africa32. In our trial, like in other studies8, maternal workload was a persistent barrier to vaccine coverage across arms and timepoints but, most importantly, in Karasuwa Local Government Area. Other previously identified barriers such as long distances to facilities, inconvenient vaccination times, long waiting times, fear of side effects and faith in immunization also varied among Local Government Areas, highlighting the importance of understanding local factors when trying to facilitate access to essential healthcare interventions31,32,33,34,35. Community engagement interventions that foster trust and address concerns about vaccines have been shown to have modest but significant positive effects on immunization outcomes36. In our study, fear of side effects decreased in both trial arms, likely reflecting ongoing community mobilization activities. This may have contributed to the increase in card-verified MCV1 coverage in the control arm and may also have contributed, in part, to increased vaccine uptake in the intervention arm. Given increasing trends in global food insecurity and nutritional crises, scaling-up SQ-LNS supplementation in some contexts is important solely for its demonstrated impact on preventing malnutrition, with Nigeria identified as one of the top 20 countries for prioritizing SQ-LNS scale-up37. Nigeria is already taking steps in this regard, having recently announced a substantial investment in SQ-LNS via the World Bank-financed Accelerating Nutrition Results in Nigeria (ANRiN) Project 2.0 (ref. 38). Results from the NutriVax-Measles trial suggest that opportunistically associating SQ-LNS distributions with routine immunizations could maximize the benefits from this investment. Strengths of this trial include its pragmatic design, with implementation at the primary healthcare level, in alignment with Nigeria’s service delivery structure, thereby enhancing external validity and policy relevance. Baseline balance between NutriVax and control arms supports internal validity and strengthens attribution of observed effects to the NutriVax strategy. The estimated intercluster contamination was low (4%), indicating low spillover of the intervention into control clusters. This does not meaningfully threaten trial integrity or inflate type I error and supports robust inference and, thus, the internal validity of the trial. Furthermore, this may reflect the publicly conducted and transparent randomization, which likely fostered community trust and adherence to trial design in a context where the absence of SQ-LNS distribution in control clusters could have otherwise led to tensions within the community or at the PHCC level. No vaccine or SQ-LNS stockouts occurred during the study implementation period thanks to good coordination between local authorities and the humanitarian organization Alliance for International Medical Action (ALIMA), maintaining the fidelity of the intervention as planned in the protocol and strengthening the internal validity of the trial. The analytical strategy combining cluster-level, marginal and DiD approaches all yielded consistent results. The very high (>99.5%) participation rates in both baseline and endline surveys is another strength that likely reflects the strong community engagement and mobilization in the NutriVax-Measles trial. We also implemented this cluster-randomized trial focusing on children in a mostly rural area with a precarious security environment in sub-Saharan Africa, supporting the important message that no one should be left out of pediatric clinical research39,40. We acknowledge several limitations. The trial was conducted in one country only, which may limit generalizability, although key contextual features observed across the different clusters—long distances to facilities, low vaccination coverage and high malnutrition prevalence—are shared by many similar settings. Parental recall, frequently used to estimate childhood vaccination coverage in the absence of vaccination cards, is imperfect; it typically shows high sensitivity but variable specificity41, which can lead to misclassification of vaccination status. Accordingly, although our primary outcome measure was vaccination verified by card, secondary outcomes relying on card or recall should be interpreted with caution. Additionally, the number of clusters per arm probably limited the precision of intracluster correlation estimates. Finally, the intervention was delivered pragmatically at points of care with minimal additional human resources. However, ALIMA provided some support to the MoH to ensure continuous availability of SQ-LNS and help prevent vaccine stockouts. Therefore, the results may not be fully generalizable to settings with less continuous supply of SQ-LNS or vaccines. Food security and the effect of SQ-LNS on nutritional status will be explored among children enrolled at 6−12 months in the longitudinal cohort, as prespecified in the statistical analysis plan, and will be reported elsewhere42. Similarly, barriers and facilitators influencing the implementation of the intervention and cost-efficiency outcomes are not reported here but will be presented in forthcoming analyses from the qualitative feasibility and the cost-efficiency substudies42. Co-delivering SQ-LNS with routine immunization in northern Nigeria substantially improved card-verified measles vaccination coverage among children aged 12−23 months. Associating SQ-LNS nutritional supplementation with routine immunization programs is a promising strategy that should be considered for scale-up in contexts facing the dual burden of high malnutrition prevalence and low vaccination coverage. Methods Reporting standards The trial is registered at ClinicalTrials.gov (NCT06387511) and is reported in accordance with Consolidated Standards of Reporting Trials (CONSORT) for cluster-randomized controlled trials and CONSORT 2025 and CONSORT–Children and Adolescents (CONSORT-C) 2026 checklists43. The full NutriVax protocol was published previously42. Study design and setting The NutriVax-Measles study was an open-label, pragmatic, superiority, two-arm, parallel, cluster-randomized trial evaluating the NutriVax strategy (intervention) against routine NPI (control) services in Yobe State, northern Nigeria. Cluster randomization was used because the intervention was delivered at the health facility level, with SQ-LNS co-delivered alongside routine immunization services, whereas its effect was assessed at the population level in the community, making individual randomization inappropriate. The trial used a pragmatic design to generate population-level evidence under real-world conditions that could inform decision-making in clinical practice and policy settings while retaining the methodological strengths of a randomized controlled trial. When systematically designed and appropriately conducted, pragmatic trials can enhance external validity and support the generalizability of findings to routine practice and to other settings with similar healthcare and program characteristics44,45. Yobe State is characterized by high prevalence of global acute malnutrition (14.2%) and severe acute malnutrition (3.7%) among children 6 months to 5 years of age; low coverage for MCV1 among children aged 12−23 months, both card verified (29.9%) and card verified or caretaker recall (59.8%); and a high proportion of zero-dose children (39.6%)22. The trial was conducted in Karasuwa and Nguru Local Government Areas, which face a precarious security situation because of activity by non-state armed groups, community violence and kidnappings. Each Local Government Area comprised 10 administrative health zones, referred to as wards, which represented the smallest administrative units used for planning and implementing health activities at health facilities and in communities. Both Local Government Areas were predominantly rural, with some peri-urban centers. Cluster eligibility was defined at the ward level: wards and their respective catchment populations within Karasuwa and Nguru Local Government Areas were eligible for inclusion, with no exclusion criteria. All 20 wards were included as clusters, enabling real-world implementation while minimizing the risk of contamination between study arms. At the time of the trial, no SQ-LNS distribution programs were planned or ongoing in the study areas. Randomization and masking Clusters, stratified by Local Government Area, were randomly assigned in a 1:1 allocation ratio to either the control arm or the NutriVax arm, so that each Local Government Area had five control and five intervention clusters. Randomization was conducted via a public lottery held separately in each Local Government Area in the local language and in the presence of MoH officials, village heads and national investigators. For each cluster, arm allocation was randomly drawn by a community representative. Randomization was stratified by Local Government Area to ensure balanced allocation and to account for differences in population, geography and sociocultural factors affecting healthcare utilization. Because cluster allocation was conducted through a public lottery, no additional allocation concealment mechanism was used. All clusters assigned to the NutriVax arm were eligible for the SQ-LNS distribution program, whereas clusters assigned to the control arm did not receive SQ-LNS through the trial. No exceptions to this allocation were made. Staff in charge of data collection were blinded to cluster allocation until completion of the baseline survey and were independent of the intervention delivery team. Caregivers and MoH and field implementation staff could not be blinded after implementation. Baseline results were masked to investigators and to MoH and field implementation staff to avoid influencing intervention delivery. Procedures Across all clusters, health services were delivered through PHCCs and health posts, which provided essential services, including treatment of malnutrition, health promotion and immunization, in accordance with MoH guidelines and policies. The Nigerian routine immunization schedule (Extended Data Table 2) was implemented by MoH staff at PHCCs, with one per cluster, and at health posts, the numbers of which ranged from zero to four across clusters. Facilities held 1−2 immunization sessions per week, during which vaccines were administered by routine MoH staff. During immunization sessions, the child’s vaccination card or history was reviewed to determine whether any scheduled vaccines were due. When a caregiver accepted the vaccination, MoH staff administered the vaccine. Catch-up doses for early childhood vaccines, including pentavalent doses, were provided for children older than 14 weeks in line with Nigerian MoH policies. MCV1 was scheduled at 9 months of age; MCV2 was scheduled at 15 months of age. (For children who did not receive MCV1 on schedule, MCV2 was scheduled at least 4 weeks after the first dose was administered.) Nutrition services were routinely available across all study clusters, independent of the trial intervention and in accordance with national guidelines. Vitamin A supplementation was provided during vaccination sessions at 6 months and 12 months of age. This was the only preventive nutritional supplementation routinely delivered in the study setting at PHCCs and health posts. Screening for acute malnutrition at PHCCs and health posts and within communities was part of routine essential primary healthcare activities and was conducted by MoH staff according to national guidelines across all clusters. Children diagnosed with acute malnutrition were referred for nutritional treatment and received therapeutic or supplementary lipid-based foods according to the severity of malnutrition at PHCCs. These routine nutrition services were available to children in both the control and NutriVax clusters, and access to treatment for acute malnutrition did not differ between study arms. In each of the 20 clusters, 10 trained community mobilizers per cluster conducted sensitization sessions at PHCCs and within communities throughout the study period. Ten additional community mobilizers were added 3 months after implementation began. Sensitization sessions followed standardized operating procedures and promoted vaccination and Infant and Young Child Feeding (IYCF) practices. Vaccination messages were aligned with the MoHʼs routine plans in Nigeria, including the Nigeria Strategy for Immunization and Primary Health Care System Strengthening 2018−2028. These messages emphasized vaccines already received, remaining doses required for full protection, return schedules and management of expected minor adverse effects. Key messages on IYCF practices were based on United Nations Childrenʼs Fund (UNICEF)-validated materials and highlighted nurturing care, age-appropriate feeding during the first 2 years of life, dietary diversity and continued breastfeeding. MoH staff and community mobilizers received financial incentives in all clusters. In each NutriVax cluster, SQ-LNS distribution was organized at PHCCs on immunization days by two trained distributors assigned to each PHCC. Eligible children were aged 6−22 months and were residents of a NutriVax cluster, without known SQ-LNS allergy. Children with acute malnutrition were not eligible to receive SQ-LNS and were referred instead for nutritional treatment according to national guidelines. They could enter or re-enter the SQ-LNS program after recovery if they remained age eligible. Caregivers of eligible children received a 1-month supply of SQ-LNS, corresponding to one sachet per day. A 3-month supply could be provided to caregivers with limited access to PHCCs or living in hard-to-reach areas. Supplementation continued until the child reached 23 months of age or had completed 12 months of supplementation, whichever occurred first. Participation was voluntary, and receipt of SQ-LNS was not conditioned on receiving a scheduled vaccine. All caregivers first entered the vaccine circuit, where the childʼs vaccination card or vaccination history was reviewed to determine whether any scheduled vaccines were due. When a vaccine was due and accepted, routine MoH staff administered the vaccine according to the national immunization schedule, either at the PHCC or at a health post, depending on facility catchment area. If a caretaker declined vaccination after counselling by a healthcare professional to address concerns, an eligible child could still receive their SQ-LNS ration at the PHCC. Thus, supplementation was not denied on the basis of vaccine refusal. During standardized sensitization sessions, communities were informed about the services available in their cluster according to trial allocation. In NutriVax clusters, these sessions included additional messages on SQ-LNS eligibility criteria and appropriate use, both at PHCCs and within communities. Participants Outcomes were assessed using a population-based endline cross-sectional survey conducted after 10 months of intervention exposure and 12 months after the baseline cross-sectional survey that had been completed before the intervention was implemented. Eligible participants were children aged 12−23 months at the time of each survey, living in the study area and with oral informed consent obtained from the parent or legal guardian. There were no exclusion criteria for the baseline survey. For the endine survey, the only exclusion criterion was participation in the longitudinal survey (see details on the other components of the trial below). Both cross-sectional surveys were conducted following the WHO reference manual for vaccination coverage cluster surveys21. Enrollment in each cross-sectional survey used a three-stage cluster sampling design, based on the estimated population of children aged 12−23 months per settlement (that is, per random units) obtained from the 2024 Yobe State MoH immunization microplanning database. In stage one, 100 settlements of 203 were randomly selected (50 per arm and five for each cluster) using the probability proportional to size sampling method. For each cluster, the cumulative estimated population of children aged 12−23 months per settlement was calculated, and the sampling interval was determined by dividing the total cumulative population by the number of settlements to be selected (n = 5). The first sampling step was generated as a random number (using R software) between 1 and the sampling interval value. In stage two, households, defined as groups of individuals sharing food and livelihood under a recognized head of household, were sampled systematically following the Multiple Indicator Cluster Surveys (MICS) methodology and templates. Large settlements with more than 900 households were divided into four segments, and those with more than 480 households were divided into two segments, with the support of community guides. Sampling intervals were calculated by dividing the estimated number of households to be visited by the number of households required to reach the target of eligible children (an anticipated non-response rate of 10.9%)22. A random starting point was selected in each segment, and households were visited sequentially according to the sampling interval until the required number of eligible children was reached. Stage three was applicable where households contained more than one eligible child aged 12−23 months, the oldest child being included under such circumstances. Detailed, standardized operational procedures and training modules were developed based on the MICS manual and tools for household mapping and selection, ensuring consistent application of the sampling plan across all clusters by trained research teams. Prior to each survey, local community leaders informed community members about the survey and its objectives. Community guides assisted with mapping, locating and facilitating access to households in each selected settlement. Outcome measures The primary outcome was coverage of MCV1 verified by vaccination card. Prespecified secondary outcomes included timeliness of card-verified MCV1 (that is, within 1 month of a child’s 9-month birthday) and coverage of other routine vaccines based on vaccination card or caregiver recall; the first and third doses of pentavalent; MCV2, the second dose of MCV; timeliness of MCV2 among children aged 15 months or older; yellow fever; and meningitis. It also included zero-dose status according to the WHO/Gavi definition (that is, having received no dose of a diphtheria−tetanus−pertussis-containing vaccine, which corresponds to the absence of pentavalent 1 vaccine); zero-dose ‘vaccine-never’ status; and fully vaccinated status. Vitamin A uptake served as an additional secondary indicator of child health service utilization because it is commonly delivered alongside routine immunization and is recorded on the Nigerian vaccination card. Post hoc secondary outcomes assessed vaccine card retention; card-verified vaccination: MCV2 among children aged 15 months or older, pentavalent 3 and zero-dose (WHO/Gavi definition); timeliness of MCV1 based on card or caregiver recall; combined card-verified zero-dose and acute malnutrition status; and combined zero-dose and acute malnutrition status based on vaccination card or caregiver declaration. Post hoc secondary outcomes assessing vaccine coverage based on vaccination card and the combined status of being zero-dose and acutely malnourished were added to complement the prespecified analyses. They were included to provide a more comprehensive assessment of vaccination coverage objectively verified by vaccination card and to characterize the double burden of being zero-dose and acutely malnourished. Uptake of SQ-LNS was recorded at endline in both arms Vaccination data were primarily obtained from vaccination cards, or from caregiver recall when cards were unavailable (except for meningococcal vaccine), using standardized WHO questionnaires, which include prompts based on route of vaccine administration and anatomical injection site (for example, Bacillus Calmette−Guérin (BCG) scar on the upper arm, pentavalent injections in the thigh and oral polio drops)21. Data were collected by trained research assistants under supervision and entered directly into REDCap (version 16.1.4) on tablet devices, with offline functionality. NutriVax-Measles embedded other populations and data collection methods, the results of which will be presented elsewhere: (1) a longitudinal 12-month follow-up household cohort of children aged 6−12 months at inclusion with last participant included before the intervention began; (2) two cross-sectional qualitative acceptability and feasibility surveys including parents/legal guardian of children aged 6−23 months, community representatives, community health workers and healthcare providers, one after 3−4 months of implementing the intervention and one during the last 2 months of the study; (3) a cost survey of caregivers of children from the longitudinal cohort; and (4) a health facility cost survey of a randomized subsample of health facilities42. Sample size Sample size, considered for cross-sectional population-based surveys, was calculated for the primary outcome assuming 30% baseline measles 1 coverage22, a conservative intracluster correlation of 0.2 (ref. 21), a 5% type I error, 90% power and 5% missing data, thus requiring 78 children per cluster per survey (total of 1,560 per cross-sectional survey) to detect a 10-pp difference in MCV1 coverage between baseline and endline46. Analyses followed intention-to-treat principles, including all randomized clusters and all participants with available endpoint data. Descriptive analyses were stratified by study arm, Local Government Area, Local Government Area-by-arm, sex and sex-by-arm (Supplementary Tables 7−10). Statistical analysis The statistical analysis plan can be accessed on ClinicalTrials.gov (NCT06387511). The primary analysis of the primary outcome used mixed-effects logistic regression with study arm and cluster-level baseline coverage as a fixed effect and cluster as a random intercept. Children without a vaccination card were classified as unvaccinated, and children with a vaccination card but no recorded MCV1 were also considered unvaccinated. Sensitivity analyses excluded children aged 21−23 months and adjusted for Local Government Area. Post hoc sensitivity analyses additionally adjusted for settlement distance to PHCC (in kilometers) and a binary variable of whether the settlement was directly served by a PHCC for immunization at endline, to account for cluster-level variability in geographic access to PHCCs (Supplementary Tables 11−13). Effects were reported as cluster-specific ORs with 95% CIs and P values derived from profile likelihood. An additional post hoc sensitivity primary analysis estimated marginal ORs from population-averaged predicted probabilities, with 95% CI and P values estimated by bootstrap. A secondary analysis of the primary outcome employed a DiD mixed-effects logistic regression with study arm, period and their interaction as fixed effects, cluster-level baseline coverage as a fixed effect and cluster as a random intercept. Effects were expressed as (1) cluster-specific ORs with 95% CIs derived from profile likelihood and P values obtained from likelihood ratio tests and (2) pp differences with 95% CIs and P values derived from parametric bootstrap (Supplementary Table 4). Mean bootstrap DiD pp estimates were calculated as a robustness measure. A post hoc sensitivity analysis additionally estimated marginal ORs derived from population-averaged predicted probabilities. ICCs were estimated as latent ICCs from the random-intercept variance on the logit scale and as observed ICCs on the probability scale using 1,000 predictive simulations of the logistic mixed-effects model, with 95% CIs from the 2.5th and 97.5th percentiles. ICCs were reported overall and by study arm. To inform the design of future cluster-randomized studies, we reported between-cluster variance estimates from the mixed-effects model (assuming a within-cluster variance fixed at π2/3 on the logistic scale, as recomended for these models47) and summarized empirical distributions of cluster-specific outcome rates at baseline and endline using the median (IQR) and range. Secondary outcomes were analyzed similarly. Secondary outcomes based on vaccination card or caregiver recall were calculated by including children with the vaccine recorded on their vaccination card as well as children without a vaccination card whose caregiver reported that the vaccine had been received. P values were adjusted using the Benjamini−Hochberg procedure to control the false discovery rate at 5% for the cluster-specific OR estimates from secondary outcomes analyses (Supplementary Table 14). For secondary outcomes for which cluster-specific ORs were estimated, post hoc sensitivity analyses additionally estimated marginal ORs from population-averaged predicted probabilities. Finally, we explored outcomes stratified by SQ-LNS uptake among children in the NutriVax clusters. This was a post hoc, non-randomized analysis. All tests were two-sided, with a type I error rate (α) set at 5%. All analyses were performed in R (version 4.4.3). Protocol deviations To limit the number of comparisons included in the Benjamini−Hochberg procedure used to control the false discovery rate at 5%, the prespecified outcomes of coverage of the first dose of pentavalent vaccine (pentavalent 1) based on vaccination card data or caregiver recall were reported descriptively (Table 2) but were not included in the multiplicity-adjusted analyses. Post hoc, we instead prioritized vaccine card retention outcome and vaccination outcomes objectively assessed using vaccination card data: card-verified zero-dose status (absence of pentavalent 1 vaccination); card-verified MCV2 among children aged 15 months or older; card-verified pentavalent 3 and meningitis vaccination; and the combined outcome of zero-dose and acute malnutrition, assessed using vaccination card data alone or vaccination card data combined with caregiver recall. Regarding vitamin A uptake, the protocol prespecified the assessment of receipt of the first dose at 6 months and the second dose at 12 months, based on vaccination card or caregiver recall. However, caregiver recall data did not allow to precisely distinguish the first and second doses or to determine the age at which those vitamin A doses were received. Consequently, we reported instead the proportion of children who had ever received at least one dose of vitamin A. Safety and adverse events The NutriVax intervention involved the co-delivery of SQ-LNS with routine immunization services, in accordance with national guidelines and the national action plan for nutrition. All preventive and curative care and follow-up procedures continued to be provided according to national guidelines, both at community level and at health facilities, throughout the trial. No additional clinical procedures or treatments were introduced as part of the study. During the baseline and endline cross-sectional household surveys, caregivers were asked about their childʼs current morbidity and if any hospitalization occurred within the 3 months preceding the interview. Ethics approval Prior to trial implementation, the study objectives, trial design, cluster allocation and SQ-LNS distribution procedures were reviewed and approved by State and Local Government Area health authorities as well as community representatives during formal meetings. Ethical approval was obtained in Nigeria from the Yobe State MoH and the Human Services Health Research Ethics Committee (MOH/GEN/747/Vol. 1) and in France from the National Institute for Health and Medical Research (INSERM) Ethics Evaluation Committee (24-1091-20240402/IRB0000388). At the cluster level, a study participation agreement was signed by the MoH PHCC manager responsible for each ward catchment area (corresponding to a cluster for the trial), after reviewing the investigator file, including the protocol and study procedures. Oral informed consent21 was obtained from parents or guardians prior to participation in both baseline and endline household cross-sectional surveys; no individual-level data were collected at health facilities. At the time of the trial, SQ-LNS was not part of the routine standard of care, and no SQ-LNS distribution programs were planned or ongoing in the study areas. Although SQ-LNS has recognized nutritional benefits and is recommended by the WHO in specific contexts, universal provision of SQ-LNS to all eligible children was not part of the existing MoH service package. The trial, therefore, did not withhold an intervention that was routinely available, planned or otherwise accessible to children in control clusters. All children in both intervention and control clusters continued to have access to routine immunization and standard nutrition services according to national guidelines under real-world programmatic and funding conditions. The trial was not designed to test whether SQ-LNS has nutritional benefits. Rather, it was designed as a pragmatic trial to evaluate a policy-relevant question: whether co-delivering SQ-LNS distribution with routine immunization services could improve vaccination coverage under real-world operational conditions. At the time of the trial, there was no evidence that this pragmatic implementation strategy conducted under conditions of genuine non-availability of SQ-LNS would improve vaccination uptake, and there was real uncertainty regarding its feasibility, effectiveness and programmatic value. Randomization was, therefore, considered ethically appropriate to rigorously assess the effectiveness and the acceptability of the intervention before any potential wider implementation. Ethics and inclusion statement Community engagement was maintained throughout the study via regular meetings with health authorities and local leaders, including, in each Local Government Area, the director or deputy director of the primary healthcare department, immunization and disease control officers, monitoring and evaluation officers, the director of family health, PHCC managers and officers in charge, nutrition officers, Local Government Area facilitators and village heads from participating clusters. Prior to trial implementation, formal meetings were held with State and Local Government Area health authorities and community representatives to review and approve the trial design and SQ-LNS distribution procedures. Randomization was conducted publicly and transparently, in the local Hausa language, with the active participation of village heads, as a deliberate safeguard to ensure acceptance of the cluster allocation process across both study arms. Engagement with stakeholders and communities was further supported through a national steering committee, comprising representatives from federal, state and local MoH, local and international nutrition and immunization actors and community leaders. These activities ensured that community leaders and state authorities remained informed of the trialʼs progress throughout implementation and were among the first to receive preliminary study findings. Nigerian co-principal investigators participated in local and national meetings and international steering committee meetings, conducted regular monitoring of investigation sites visits and participated in dissemination activities of preliminary results at state and national levels. After trial completion, Yobe State authorities allocated a dedicated SQ-LNS budget informed by the study findings, illustrating the sustained stakeholder engagement and research-to-policy translation underpinning this pragmatic trial. Data ownership and authorship were shared with researchers from Yobe State University Teaching Hospital, Ahmadu Bello University, Yobe State Healthcare and Related Facilities Inspection and Monitoring Agency and Ahmadu Bello University (Zaria, Nigeria). Even though SQ-LNS has strong scientific evidence, the lack of international and domestic investment has led to slow uptake. The study team advocated for financing of SQ-LNS to continue after the trial but could not secure the funding. The Yobe State government did, however, commit to purchasing SQ-LNS in their 2026 budget, in large part due to an initiative led by UNICEF called the Child Nutrition Fund (CNF) in which international donors match domestic investments in nutritional commodities. After the trial ended, the government of Nigeria and the World Bank also announced ANRiN Project 2.0, which includes substantial financing for SQ-LNS, some of which will be allocated to the areas where NutriVax was conducted. Sustainability of SQ-LNS programming will depend on dedicated financing like this as well as building the capacity of MoH staff to manage such distribution programs. This study was conducted as part of the Clinical and Operational Research Alliance (CORAL), a consortium aimed at developing high-quality, innovative and transformative global health research programs through a collaboration between scientists from the Bordeaux Population Health Research Center (Bordeaux, France) and the PAC-CI Research Program (Abidjan, Côte d’Ivoire) and the humanitarian organization ALIMA (Dakar, Senegal), with a focus on improving maternal and child health outcomes in sub-Saharan Africa and Haiti. Confidentiality All study data were securely stored and managed to protect participant confidentiality, with participants identified only by a unique identifier. No personal data were recorded in the database. Data access was encrypted and restricted to the research team. Reporting summary Further information on research design is available in the Nature Portfolio Reporting Summary linked to this article. Data availability A deidentified individual-level dataset required to reproduce the primary and secondary analyses will be made available subject to certain conditions within 3 months after publication through the IRD DataSuds repository (https://dataverse.ird.fr/) with an assigned study DOI, in accordance with institutional requirements for the data curation process. The data will remain available for at least 15 years. Access will be granted after evaluation of a research proposal submitted along with the request based on its scientific merit, methodological soundness and compliance with the ethical and legal requirements of Nigerian, European and French regulations on the protection of personal data. Requests for access to the data and code should be submitted through the DataSuds repository using the dataset DOI and will be reviewed by the corresponding author (INSERM/IRD principal investigator) at renaud.becquet@u-bordeaux.fr. A decision will be provided within 4 weeks of receiving the request. Approved applicants will receive access to the dataset and code through the IRD DataSuds repository. Code availability Statistical code required to reproduce the primary and secondary analyses will be made available subject to certain conditions within 3 months after publication through the IRD DataSuds repository (https://dataverse.ird.fr/) with an assigned study DOI, in accordance with institutional requirements for the data curation process. The code will remain available for at least 15 years. Requests for accessing the code should be submitted through the DataSuds repository using the DOI and will be reviewed by the corresponding author (INSERM/IRD principal investigator) at renaud.becquet@u-bordeaux.fr. A decision will be provided within 4 weeks of receiving the request. Approved applicants will receive access to the dataset and code through the IRD DataSuds repository. References Morales, F., Montserrat-de la Paz, S., Leon, M. J. & Rivero-Pino, F. 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We are deeply grateful to the healthcare workers, community mobilizers, PHCC managers, Local Government Area authorities and the Yobe State MoH directors and officers for their commitment and support throughout the study as well as the ALIMA operational teams who contributed to trial implementation and support. We also acknowledge the valuable support and guidance provided by the members of the national steering committee throughout the NutriVax project. We also thank V. Journot (Bordeaux Population Health Research Center, France) for advising the study team on the trial methodology; G. G. Habiyambere (Bordeaux Population Health Research Center, France) for participating in study documents conception and in the writing of the data monitoring plan; M. Huyen (Bordeaux Population Health Research Center, France) for reviewing the statistical analysis plan; and S. Karcher (Bordeaux Population Health Research Center, France), J. Le Carrou (Bordeaux Population Health Research Center, France), C. Nchot (PAC-CI Research Program, Ivory Coast) and A. Kouame (PAC-CI Research Program, Ivory Coast) for supporting the data storage and data management. We are also indebted to the members of the scientific committee for the NutriVax-Measles trial: K. Dewey (University of California), I. Trehan (University of Washington), L. Huybregts (International Food Policy Research Institute), S. de Pee (World Food Program) and A. Connor (IDinsight), whose extensive experience conducting individual and cluster-randomized control trials, including some with SQ-LNS, provided valuable methodological and ethical guidance before and during the study. Funding This study was funded by the Eleanor Crook Foundation (ECF) (USA) and Gavi, the Vaccine Alliance (Switzerland). Gavi’s support was provided through the Gavi Matching Fund, with the UK Foreign, Commonwealth and Development Office (FCDO) as the Matching Fund donor. This study also benefited from the expertise of the Franco-Ivorian Clinical Trial Unit MEREVA, embedded within the PRISME-CI platform (Plateforme de Recherche Internationale en Santé Mondiale pour la Côte d’Ivoire). PRISME-CI is primarily funded by the French national agency ANRS Emerging Infectious Diseases (ANRS-MIE, France) with additional support from the French National Institute for Health and Medical Research (INSERM, France), the French National Institute for Sustainable Development (IRD, France), the University of Bordeaux (France), the ministries for Health, Higher Education and Finance of the Republic of Côte d’Ivoire and the French embassy in Côte d’Ivoire. This study is part of the ‘IPORA – Interdisciplinary Policy-Oriented Research on Africa’ consortium that benefited from French public funding managed by the University of Bordeaux under the France 2030 plan. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The views expressed herein should not be taken, in any way, to reflect the official opinion of the ECF, Gavi or ANRS-MIE, and these organizations are not responsible for any use that can be made of the information that this work contains. Author information Authors and Affiliations Contributions K.P. developed the intervention strategy and led the funding acquisition, with substantial contributions from C.M., O.A., C.C. and R.B. R.B. and C.C. developed the study methodology. D.G. wrote the statistical analysis plan and conducted sample size calculations and all analyses. N.S., B.W.G., H.M.A. and U.C. were involved in the conceptualization of the study and ensured alignment with local guidelines and practices. K.P. and C.C. coordinated the operational and study teams. B.W.G., N.S.M. and J.N. ensured the implementation of the study protocol, and I.A., J.N., A.M.A., E.C.U., S.B., H.M.A., U.C., F.I., M.K. and M.M.A.B. ensured the implementation of intervention activities in the study sites and in the community. M.C. and J.-P.M. contributed to the overall administration of the project. C.C. and B.Y. organized data collection, wrote standardized procedures, provided training support and supervised the international monitoring. O.O. supervised data collection and national monitoring of the baseline and endline cross-sectional surveys. S.D. and E.B. developed and managed the database. B.W.G. and N.S.M. supervised the MoH staff working in the study sites. B.Y., D.G. and C.C. verified the underlying data of the study. D.G. performed the statistical analysis, and D.G., C.C., B.W.G., J.N., R.B. and K.P. interpreted the results. C.C. wrote the first draft of the manuscript, with substantial inputs from K.P. and R.B. All co-authors reviewed the first draft of the manuscript. K.P. and R.B. had final responsibility for the decision to submit the manuscript for publication. Corresponding author Ethics declarations Competing interests K.P. reports a past relationship with Nutriset SAS that includes consulting and advisory roles. The other authors declare no competing interests. Peer review Peer review information Nature Medicine thanks Rashida Ferrand, Ane Fisker, Matthew Coldiron, Boghuma Titanji and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available. Primary Handling Editor: Ming Yang, in collaboration with the Nature Medicine team. Additional information Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. 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To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/. About this article Cite this article Cazes, C., Goni, B.W., Gabillard, D. et al. Small quantity lipid-based nutritional supplementation and measles vaccination coverage in children aged 6−23 months: a pragmatic cluster-randomized trial. Nat Med (2026). https://doi.org/10.1038/s41591-026-04675-1 Received: Accepted: Published: Version of record: DOI: https://doi.org/10.1038/s41591-026-04675-1