Abstract / Summary
Abstract Background Children who do not receive the first dose of the diphtheria-tetanus-pertussis-containing vaccine (DTP1) during their first year of life are referred to as zero-dose children. Zero-dose children remain a significant public health challenge in Tanzania. Their exclusion from routine vaccination services creates substantial immunity gaps, increasing the risk of outbreaks of vaccine-preventable diseases and undermining efforts to achieve equitable health outcomes for all children. Identifying where these children live and determining effective strategies to reach them are essential for achieving equitable immunisation coverage. This study aimed to map, identify, and investigate strategies for reaching zero-dose children in Tanzania. Methods A cross-sectional mixed-methods study was conducted using document reviews, observation checklists, and key informant interviews (KIIs). 21 immunisation-related documents were reviewed, and 44 health facilities were assessed for defaulter tracking practices. Key informant interviews were conducted with 52 government officials and healthcare providers involved in childhood immunisation programmes. Document review data were analysed using content analysis, observation checklist data were analysed descriptively using frequencies and percentages, and interview data were analysed thematically. Results According to the 2025 Ministry of Health Immunisation and Vaccine Development (IVD) supportive supervision report, 67% of health facilities had developed Reaching Every Child (REC) microplans,78% had scheduled routine vaccination sessions, 72% had established zero-dose tracking mechanisms, 31.8% had defaulter-tracking systems, and 64% maintained immunisation monitoring charts. Direct observations further confirmed that tracking and monitoring systems were operational in most of the health facilities assessed. Qualitative findings identified outreach, mobile, and integrated vaccination services as the primary strategies for reaching zero-dose children in underserved and hard-to-reach communities. Community health workers and local leaders played critical roles in community mapping, household identification of unvaccinated children, caregiver mobilisation, and defaulter tracing. Conclusion Tanzania has established several mechanisms for identifying and reaching zero-dose children, including REC microplanning, tracking systems, community engagement structures, and routine monitoring tools. Integrated service delivery approaches, supported by community health workers and local leaders, were identified as key strategies for reaching underserved populations and improving access to immunisation services. The strengthening and full institutionalisation of these systems at national and subnational levels are essential for ensuring their long-term sustainability.