30 years of polio campaigns in Ethiopia, India and Nigeria: the impacts of campaign design on vaccine hesitancy and health worker motivation

This study addresses how mass polio vaccination campaigns interact with national health systems over time and how these interactions influence frontline health worker (FLHW) motivation and vaccine hesitancy, thereby affecting oral polio vaccine (OPV) campaign coverage. The authors situate the work in a long-standing debate about vertical programmes’ impacts on health systems, noting prior tendencies to assess effects separately from programme outcomes and to classify them as positive or negative. Recognizing health systems as complex, dynamic, and interconnected, the study proposes a complex adaptive systems (CAS) lens to explicitly articulate relationships and feedbacks between system elements. Using Ethiopia, India, and Nigeria—countries with extensive polio campaign activity and differing health system capacities—the analysis seeks to illuminate path-dependent, unintended consequences of campaign design choices (such as reliance on parallel structures and campaign frequency) for worker motivation and community trust. The work is timely given ongoing global vaccination efforts, including COVID-19, where campaign design and integration with routine systems are central to effectiveness and sustainability.

The paper reviews 25 years of research on how mass campaigns affect health systems, referencing early work (Taylor Commission) that characterized impacts by health system component and as positive/negative, while cautions were raised about generalizability. Subsequent studies documented the tensions between campaign-based and routine delivery strategies and challenges in leveraging eradication initiatives for health systems strengthening. Despite advances, much prior work retained static, binary frameworks. Systems thinking approaches have been applied in global health but remain underused; CAS perspectives emphasize path dependency, feedback loops, and unintended effects. The authors highlight renewed relevance in the COVID-19 era, where maximizing campaign effectiveness and supporting health systems are concurrent goals. They also reference literature on vaccine hesitancy, routine immunization drivers, and examples of co-delivery and integration, motivating a dynamic analysis linking campaigns, health systems performance, FLHW motivation, and community trust.

Design: Qualitative, inductive construction of a causal loop diagram (CLD) to depict interactions between polio campaigns and government health systems in Ethiopia, India, and Nigeria. Data sources: (1) Polio Eradication Impacts Study (2011–2012): 175 semi-structured interviews with national, district, and frontline actors; country totals: Ethiopia (n=55), India (n=85), Nigeria (n=35). (2) STRIPE study (2019): 101 semi-structured interviews with implementers at national, district, frontline, and global levels; country totals: Ethiopia (n=30), India (n=25), Nigeria (n=29), plus global policy-makers (n=17). Consent was oral; confidentiality maintained. Additional literature review on polio eradication in the three countries. Participants: Policymakers, officials (national/district), and FLHWs (community health workers, health extension workers, vaccination staff). Analysis: Pre-identified mediating variables from prior studies grouped into five themes: FLHWs; supervisory structures; politics and government-community relations; health system quality/responsiveness; reliance on mass campaigns. Previously coded materials from both studies were collated by theme. Three analysts each focused on a single country, wrote extensive memos tracing dynamics over time, and met weekly for cross-country synthesis. Each analyst independently drafted a country-specific CLD; discrepancies were discussed to reach shared understanding. A consolidated cross-country CLD was iteratively refined to ensure fidelity to inductive findings, inclusion of key concepts, interpretability, and was validated by in-country coauthors. Approach emphasized qualitative standards for inductive theory development; no quantitative testing of the CLD was undertaken. Contextual country profiles documented campaign frequency, integration, and health system features (e.g., India’s intense campaign schedule up to 10–12/year in certain northern districts; Ethiopia’s diagonal approach with 1–2 national campaigns/year and up to five subnational during outbreaks; Northern Nigeria’s every-other-month campaigns over a decade).

- Frequent campaigns via parallel structures in weaker health systems led over time to reduced FLHW motivation and increased vaccine hesitancy, undermining OPV campaign coverage. - Path dependency: Establishing parallel systems—often intended as temporary—pushed programmes toward increasing campaign frequency and reduced accountability to local communities, especially where routine immunization (RI) and primary health care (PHC) were weak. - Differential context effects: • Stronger systems (e.g., South India, parts of Ethiopia): few campaigns integrated through government structures; polio resources supported surveillance, cold chain, and training beyond polio; fewer issues with fatigue or hesitancy. • Weaker systems (e.g., North India, Northern Nigeria): intense campaign schedules (up to 11–12 rounds/year in North India; ~8/year in Northern Nigeria) with many partner-funded staff created parallelism; health facilities often underperforming; communities perceived misaligned priorities. - FLHW workload and fatigue: High campaign frequency drove fatigue and demotivation; FLHWs juggled multiple vertical programmes with different workflows and reporting lines. In Bihar, India, FLHWs spent at least 77 days per year on polio campaigns alone. Even with fewer campaigns (e.g., Ethiopia), broad task portfolios (16 service packages for Health Extension Workers) strained capacity. - Reinforcing feedbacks: • FLHW motivation and community trust formed a reinforcing loop—motivated, trusted workers improved engagement and coverage, further boosting trust and motivation. • Conversely, fatigue and perceived misaligned priorities eroded performance and trust, reinforcing hesitancy. - Community trust and hesitancy: Trust in polio campaigns was strongly linked to trust in the broader health system. In underserved areas, frequent house-to-house polio visits amidst poor access to other services triggered suspicions and strategic “demand refusals” (rejecting OPV to press for other services like drugs, food supplements, or malaria treatment). - Co-delivery mitigated negative dynamics: Adding Vitamin A, ITNs, deworming, nutrition screening, diarrhea/ORS messaging, and focused RI efforts (e.g., India’s 107 Block Plan) improved responsiveness, reduced fatigue via streamlined workflows, increased community trust, and contributed to successful polio elimination in India. - Time dynamics: Negative effects (fatigue, hesitancy) were slow-burning, emerging over years of repeated campaigns; short-term gains from parallelism and frequent campaigns could erode over time without integration or co-delivery.

Using a CAS and CLD approach revealed dynamic, interconnected pathways by which polio campaign design interacts with health systems and communities. Feedback loops between FLHW motivation and community trust, and path-dependent effects of parallelism and campaign frequency, help explain why campaigns became less effective over time in weaker systems. The analysis refines understandings of vaccine hesitancy by linking it to system responsiveness and perceived accountability to community priorities, not solely to community-internal factors. Co-delivery of broader interventions can interrupt negative feedbacks by improving frontline workflows and aligning services with community needs, thereby restoring trust and sustaining coverage. However, reliance on externally funded vertical structures for broader service delivery raises sustainability concerns. The CLD method offers an analytical advantage for visualizing feedback and time-dependent effects and can be applied to other vertical programmes (e.g., HIV, malaria, COVID-19) and to planning for donor transitions or anticipating unintended consequences of new initiatives.

Polio campaign effectiveness over the long term depends on designs that account for complex health system dynamics and community priorities. Key recommendations include: (1) Limit reliance on single-disease, parallel campaign structures; integrate activities into national systems wherever possible. (2) Where parallelism cannot be avoided, prioritize co-delivery of relevant health services to improve responsiveness and mitigate fatigue and hesitancy. (3) Deliberately manage FLHW workload and provide supportive supervision and incentives to reduce campaign fatigue and sustain motivation. (4) When targeting issues that are not top community priorities, conduct needs assessments and pair campaigns with interventions that address those priorities. Recognizing path dependency and feedback loops in health systems is essential to designing sustainable, acceptable, and effective mass vaccination campaigns.

The analysis is qualitative and based on interviews and literature; CLD relationships were not quantitatively tested. Although diverse respondents were included across levels and countries, additional perspectives—especially from caregivers and health managers outside the polio programme—could have enriched findings. Generalizability may be limited by contextual differences, and the reliance on parallel polio structures to deliver broader services raises questions about sustainability beyond external funding.