New perspectives on persistent zero-dose themes
New evidence from Gavi’s Zero-Dose Learning Hub shows how aggregated data, fragmented systems and national level assumptions can leave missed communities unseen.
- 17 March 2026
- 7 min read
- by JSI
When immunisation programmes struggle to reach under-immunised children, the default advice is familiar: improve data, secure more funding and expand outreach to ‘hard-to-reach’ places.
These steps matter, but Zero-Dose Learning Hub (ZDLH) evidence shows they are incomplete. Data is only useful when it triggers accountability and response, and reaching missed children requires budgets and delivery strategies designed around local realities, not national averages or assumptions.
As the global learning partner for the Gavi-funded ZDLH, JSI has synthesised evidence from Country Learning Hubs in Bangladesh, Mali, Nigeria and Uganda to capture what implementation research has revealed.
The result is a clearer view of where routine reporting hides the zero-dose burden, how fragmented systems distort decisions and why institutional conditions often determine whether strategies succeed. These insights offer a practical roadmap for more resilient, efficient immunisation systems.
Zero-dose burden is dynamic, localised and often obscured by current reporting
Immunisation programmes frequently rely on national and district-level administrative data systems to guide targeting and resource allocation.
DHIS2 is the primary source of routine data used by district teams to monitor immunisation coverage and direct resources to underserved areas. However, Learning Hub evidence shows that DHIS2 can mask the zero-dose burden through aggregation and denominator challenges. When data is summarised at district levels and above, localised pockets of missed children disappear.
In Bangladesh, the Learning Hub’s periodic review of DHIS2 data over a period of three years showed that zero-dose pockets shifted from year to year, with high-burden areas expanding or relocating over time. These patterns demonstrate how static zero-dose estimates can miss rapid changes, particularly when system shocks such as workforce disruption, vaccine supply interruptions, or broader instability affect service delivery conditions.
In some areas, administrative coverage rates even exceeded 100% because population estimates were outdated or children were vaccinated outside their catchment area, but were still included in the original catchment area’s denominator. This creates an illusion of high coverage while missed communities remain hidden.
Nigeria’s decentralised immunisation monitoring (DIM) approach reinforces this granularity gap’. By using lot quality assurance sampling (LQAS) to assess routine immunisation performance at the subdistrict (e.g. ward) level, the DIM generated timely, actionable data that district averages often fail to reveal, showing sharp disparities across contexts, including poorer performance of vaccination services in wards located in some rural areas than in urban centres.
Takeaway
In Gavi’s 2026–2030 strategic period, programming should prioritise monitoring and measurement approaches that detect subdistrict variability and shifting zero-dose hotspots, rather than relying solely on national or district-level estimates.
Fragmented data systems produce discrepant zero-dose estimates
Countries are increasingly operating within fragmented data ecosystems: multiple donor-supported tools, parallel reporting systems and non-interoperable platforms. Learning Hub findings show that this fragmentation tends to generate discrepant zero-dose estimates, increase workload for frontline workers and slow real-time decision-making.
In Mali, fragmentation across DHIS2, paper systems and programme-specific tools impeded the efforts of district teams to triangulate data and limited their ability to track children over time. These system disconnects reduce follow-up and continuity of care precisely where the zero-dose challenge is most persistent.
Takeaway
During the strategic period 2026–2030, Gavi investment should prioritise integration, triangulation and interoperable systems that enable actionable data use, rather than additional standalone tools.
Gender and household dynamics can outweigh physical access
Immunisation strategies often prioritise geography and service availability as key drivers of low vaccination uptake. Learning Hub evidence shows how household decision-making dynamics and gender norms can be equally or more determinative than distance to services.
Across varied contexts in the Learning Hub countries, poverty, low education and misinformation persist as barriers to vaccination, but these are frequently structured by caregiver agency, social norms and household power dynamics.
As a result, behavioural barriers can prevent vaccination even where services are geographically available. Geographic prioritisation alone is therefore incomplete as a strategy for reaching missed children.
Takeaway
Strategies to identify and reach zero-dose and under-immunised children during Gavi's 2026–2030 strategic period should incorporate social profiling (education, household constraints, caregiver agency) alongside geographic mapping.
Reaching zero-dose children requires precision budgeting, not broad estimates
Budgeting discussions often treat reaching zero-dose children as universally expensive and addressable through generalised resource expansion. Learning Hub costing work demonstrates a more operational reality: there is no single ‘cost to reach a zero-dose child’. Costs vary widely by delivery model and subnational context.
In Uganda, the incremental cost to vaccinate a zero-dose child with the first dose of the diphtheria, tetanus and pertussis-containing vaccine (DTP1) ranged from US$ 8.30 in one rural district to US$ 68.70 in another that was largely mountainous. The wide range in costs was driven by granular differences such as population density, delivery strategy and logistical constraints due to the local geography. Uniform budgeting and scale-up without cost-effectiveness analyses can create inefficiency, overfunding some settings while leaving the most challenging areas under-resourced.
Takeaway
Countries and partners should cost and scale interventions based on local operational realities and efficiency gains, not national averages.
Locally-tailored innovations remain vulnerable to upstream failures
Through rigorous implementation research, the Learning Hubs have documented the success of different evidence-based local innovations: from evening immunisation sessions in Bangladesh to digital coaching tools supporting delivery in Mali.
Yet Learning Hub evidence also shows that well-designed interventions remain vulnerable to chronic upstream failures that can erase gains. Across the four countries, local success was frequently undermined by administrative bottlenecks, delayed approvals of operational plans, vaccine shortages and workforce instability.
In Bangladesh, high vaccinator vacancy rates and delayed payments weakened both identification and reach of zero-dose children. In Mali, insecurity prevented data collection in some districts, signalling that the true zero-dose burden may be higher in precisely the areas where traditional measurement and service delivery are most constrained.
Takeaway
During the Gavi 2026–2030 strategic period, scale-up plans should address upstream bottlenecks like financing, supply reliability, and workforce stability so that local innovations can be sustained.
The effectiveness of data hinges on institutional factors
Data improvement efforts often assume that better information (e.g. timely, accurate, complete, reliable and relevant) automatically produces better outcomes. However, evidence from the Learning Hub suggests a more complex reality. High-quality data is only as effective as the systems built to act on it, including political commitment, accountability structures and institutional alignment.
In Nigeria, the use of Immunisation Accountability Scorecards demonstrated how linking performance data to political attention can drive tangible action, including the release of previously stalled immunisation budgets. In this case, data acted as a lever for financial accountability, garnering political attention to unlock budgets. A similar situation exists at decentralised levels.
For example, in Uganda, subnational and frontline actors effectively identified missed children but lacked the authority or sustained resources to respond. A total of 99 zero-dose children were identified in a baseline study, yet a follow-up study one year later by the Learning Hub found most remained unvaccinated, reflecting weak follow-up mechanisms to close the loop from identification to vaccination.
Takeaway
Investments in data and digital tools during the Gavi 2026–2030 strategic period should be paired with governance, authority and financing mechanisms that enable subnational action.
Carrying the learning forward
As global funding tightens and Gavi’s 2026–2030 strategic period priorities evolve, these insights offer a timely opportunity to carry the learning forward.
The next phase of progress will come from applying what implementation has made clear: invest in subdistrict visibility, reduce fragmentation of data, design for household and gender dynamics, budget delivery models based on local costing realities, and strengthen accountability so evidence leads to action.
JSI is consolidating and sharing these lessons from the Bangladesh, Mali, Nigeria and Uganda Learning Hubs to support countries and partners as they shape priorities for Gavi 6.0 and beyond.
