Review 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 Umar Yunusa a,⇑ , Saleh Ngaski Garba a , Addakano Bello Umar b , Suleiman Hadejia Idris c,d , Umar Lawal Bello a , Idris Abdulrashid a , Jibril Mohammed e a Department of Nursing Sciences, Bayero University, Kano, Kano State, Nigeria b Department of Nursing Sciences, Ahmadu Bello University, Zaria, Kaduna State, Nigeria c Department of Community Medicine, Ahmadu Bello University Zaria, Kaduna State, Nigeria d Department of Community Medicine, Federal Medical Center, Birnin Kudu, Jigawa State, Nigeria e Department of Physiotherapy, Bayero University, Kano, Kano State, Nigeria article info Article history: Received 16 August 2020 Received in revised form 14 October 2020 Accepted 12 November 2020 Available online xxxx Keywords: Immunization outcomes Mobile phone intervention Reminder Child health LMICs abstract Immunization remains one of the most effective public health interventions offering protection for chil- dren 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 stud- ies. 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 benefi- cial. 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 mod- erate. 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. Ó 2020 Elsevier Ltd. All rights reserved. Contents 1. Introduction .......................................................................................................... 00 2. Methodology.......................................................................................................... 00 2.1. Protocol and registration .......................................................................................... 00 2.2. Eligibility criteria ................................................................................................. 00 https://doi.org/10.1016/j.vaccine.2020.11.043 0264-410X/Ó 2020 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department of Nursing Sciences, Bayero University Kano, P.M.B. 3011, Kano State, Nigeria. E-mail address: uyunusa.nur@buk.edu.ng (U. Yunusa). Vaccine xxx (xxxx) xxx Contents lists available at ScienceDirect Vaccine journal homepage: www.elsevier.com/locate/vaccine Please cite this article as: U. Yunusa, Saleh Ngaski Garba, Addakano Bello Umar et al., 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, Vaccine, https://doi.org/ 10.1016/j.vaccine.2020.11.043