RESUMO
INTRODUCTION: There is growing interest among low- and middle-income countries to introduce electronic immunization registries (EIRs) that capture individual-level vaccine data. We compare the design, development, and deployment of EIRs in Vietnam, Tanzania, and Zambia. Through desk review and the authors' firsthand implementation experiences, we describe experiences related to timeline, partnerships, financial costs, and technology and infrastructure. IMPLEMENTATION EXPERIENCE: The country cases highlight the multi-year timeline required to implement an EIR at scale and the benefit of multiple iterative cycles to pilot and redesign the system before achieving scale. Of the 3 countries, only Vietnam has achieved nationwide scale of the EIR, which took 7 years. In all 3 countries, national government leadership as part of an interdisciplinary team (with experience in leadership, technology, and immunization) was important to ensure country ownership and sustainability. Where international software developers were contracted, partnering with a local software company helped improve responsiveness and sustainability. Across all 3 countries, governments contributed significant in-kind time in addition to investments from donors. Cost savings were observed in Tanzania and Zambia, largely driven by health worker time savings from using the EIR. All 3 case countries underscore the need to understand the local technology and infrastructure context and design the EIR to fit the context. In Vietnam, an initial landscape assessment was conducted to assess technology and infrastructure, whereas in Tanzania and Zambia, user advisory groups provided insights. Existing infrastructure informed EIR design decisions, such as choosing a system with offline functionality in Tanzania and Zambia. All 3 countries have a local partner to provide ongoing technical support. CONCLUSION: Comparing implementation factors across these cases highlights practical experience and recommendations that complement existing EIR guidance documents. The findings and recommendations from this study can inform other countries considering or in the process of implementing an EIR.