Background:
Achievement in the national Expanded Programme on Immunization (EPI) is globally recognized as an example in Low- and Middle-Income Countries (LMICs). However, the 2019 Coverage Evaluation Survey (CES) shows that 84% of children are fully vaccinated nationally. Digital solutions like mobile phone help reduce vaccination program challenges. Therefore, Bangladesh has been implementing a pilot intervention of individual electronic tracking (e-tracking) of children in Moulvibazar District and Dhaka South City Corporation and planning to scale it up.

Objective:
The current implementation research was conducted to understand the implementation process, success, and challenges of the e-Tracker system in Bangladesh and obtain lessons learned and scaling-up recommendations.

Methods:
The study followed the embedded mixed-method design, including both beneficiaries and implementers. This study occurred in selected areas of Moulvibazar District and Zone-5 of Dhaka South City Corporation and lasted from 1st April to 30th June 2021. A secondary analysis of existing vaccination coverage data of both the e-Tracker and the paper-based system was performed. Data were analyzed using Re-AIM Implementation Framework.

Results:
According to the implementors, they get individual accurate coverage data, minimize dropouts, avoid mistakes, monitor, and recognize invalid doses from a single device. The caregivers receive SMS reminders of the child’s vaccination date, yet many reported not receiving the SMS regularly. The frontliners, mostly from urban were comfortable using the e-Tracker app; however, the ageing rural field workers initially struggled to use the device. The e-tracker system creates additional load and requires regular troubleshooting and will require regular internet support and technical staff, especially from the government.

Conclusion:
This study found that the e-Tracker can produce accurate real-time data and identify dropouts; however, we need technology friendly manpower, feasible technology, the uninterrupted internet, and logistics support with a sustainable maintenance mechanism to implement and scale up this technology-dependent intervention successfully.