mHealth: a narrative synthesis of evidence of its application in improving childhood immunization coverage
Under-5 mortality from preventable causes remains a significant problem in many parts of the developing world. Deaths from vaccine-preventable diseases (VPDs) continue to challenge the health care system of these countries, despite unrelenting efforts to expand routine immunization coverage. Despite the proven efficacy of these vaccines, several supply and demand-side factors, as well as other context-specific factors have been associated with the poor uptake and completion rates, and the consequent high mortality rates from VPDs in these countries. In addition to specific policy and health system-related approaches to addressing these factors, inconsistent literature evidence suggests the potential efficacy of several range of interventions such as promoting antenatal care attendance and hospital delivery, providing education, financial incentives and deployment of mobile health technology (mHealth: SMS and telephone call reminders), in improving childhood immunization coverage in several countries across Africa, Asia and North America. This mini-review explored the diversity and quality of evidence regarding the application of mHealth in improving childhood immunization coverage. Following a brief search on Scimago Journal and Country Rank using a combination of relevant subject areas and subject categories, we finally evaluated 15 articles—mainly systematic reviews  and randomized controlled trials (RCTs) —published in 12 top Q1 impact factor journals between 2010 and 2017. Overall, we found moderate to high-quality literature evidence suggesting the efficacy of mHealth interventions used singly or in combination with other interventions in improving childhood immunization coverage across several rural and urban settings around the world. While these evidences represent the larger consensus, we recommend that more attention should be given to detailed analysis of factors or circumstances that lead to negative results of these interventions in areas where such have been observed or reported.