Mobile phone reminders for enhancing uptake, completeness and timeliness of routine childhood immunization in low and middle income countries: A systematic review and meta-analysis

Immunization remains one of the most effective public health interventions offering protection for children from vaccine preventable diseases. However, many children living in low- and- middle income countries do not get adequate immunization due to several factors. Mobile phone reminder interventions have shown great potential in enhancing a number of immunization outcomes. However, the evidence supporting its use in these countries is vague. This systematic review was conducted to provide evidence for mobile phone reminder in enhancing immunization uptake, completeness and timeliness. This review was conducted in accordance to the PRISMA recommendations. Three online databases; PubMed, Cochrane Library and African Journals Online, were systematically searched for potentially relevant studies. Screening of records (titles/abstracts from and full-texts) was done using Covidence. Meta-analyses were conducted using the Cochrane Collaboration Review Manager (v5.4). The GRADEpro was used to evaluate the certainty of evidence/summary of findings. Eleven RCTs assessing immunization uptake, completeness and/or timeliness by means of SMS, phone calls or a combination of voice message and SMS were included in both quantitative and qualitative synthesis. Overall, the included studies were of moderate quality. Majority of the included studies indicated that mobile phone reminders were beneficial. Meta-analyses indicated that using mobile phone reminder interventions for the review outcomes was of variable effect with high level of heterogeneity. A combination of voice message and SMS has a greater effect followed by phone calls then SMS reminders for immunization completeness. The use of SMS for immunization uptake and timeliness were largely insignificant (p > 0.05). Furthermore, evidence to support the efficacy of mobile phone reminder from the GRADE synthesis was between low and moderate. Mobile phone reminders, particularly a combination of voice message + SMS and perhaps phone calls appears to be more effective in enhancing immunization outcomes. However, more studies are required in view of methodological inadequacies in existing studies.