Effectiveness of a smart phone app on improving immunization of children in rural Sichuan Province- China: study protocol for a paired cluster randomized controlled trial.

BACKGROUND: Although good progress has been achieved in expanding immunization of children in China- disparities exist across different provinces. Information gaps both from the service supply and demand sides hinder timely vaccination of children in rural areas. The rapid development of mobile health technology (mHealth) provides unprecedented opportunities for improving health services and reaching underserved populations. However- there is a lack of literature that rigorously evaluates the impact of mHealth interventions on immunization coverage as well as the usability and feasibility of smart phone applications (apps). This study aims to assess the effectiveness of a smart phone-based app (Expanded Program on Immunization app- or EPI app) on improving the coverage of children's immunization. METHODS/DESIGN: This cluster randomized trial will take place in Xuanhan County- Sichuan Province- China. Functionalities of the app include the following: to make appointments automatically- record and update childr