Zero-dose children in Kano State, Nigeria: a multi-site qualitative study of non-initiation and social and behavioural change communication levers

Zero-dose children are increasingly concentrated in underserved communities, with progress stagnating despite improved routine immunisation coverage. Nigeria is a high-burden country, with Kano State a high-zero-dose setting, despite investments, highlighting that technical service adequacy alone cannot overcome gaps in caregiver trust for services. The study draws on behavioural and systems frameworks that view vaccine uptake by cognitive, social, and structural factors. The 5 C model (confidence, complacency, constraints, calculation, collective responsibility) and 5 As (access, affordability, awareness, acceptance, activation) guide interpretation of trust, risk perception, and logistical realities within immunisation systems and social communication. A qualitative multi-site design included 44 focus groups with caregivers, leaders, and mobilisers, and 50 interviews with providers and officials across five Kano LGAs. Data were collected using Hausa-translated guides, transcribed, and coded in NVivo 14 through a combined deductive–inductive approach with double coding for rigour. Respondents described a coverage paradox where immunisation programmes coexist with zero-dose pockets. Barriers included fear of side effects, poverty, and distrust of free services. Levers included faith-led engagement, mobilisers, and pain-relief guidance. Zero-dose cases in Kano reflect perceived vaccine risk and economic hardship, interacting with concerns about service quality, necessitating equity-focused communication through trusted messengers.