Article Text

Short message service (SMS) reminders for childhood immunisation in low-income and middle-income countries: a systematic review and meta-analysis
  1. Paul Eze1,
  2. Lucky Osaheni Lawani2,
  3. Yubraj Acharya1
  1. 1Department of Health Policy and Administration, Pennsylvania State University, University Park, Pennsylvania, USA
  2. 2Institute of Health Policy, Management & Evaluation, University of Toronto, Toronto, Ontario, Canada
  1. Correspondence to Paul Eze; peze{at}


Introduction Childhood vaccine delivery services in the low- and middle-income countries (LMIC) are struggling to reach every child with lifesaving vaccines. Short message service (SMS) reminders have demonstrated positive impact on a number of attrition-prone healthcare delivery services. We aimed to evaluate the effectiveness of SMS reminders in improving immunisation coverage and timeliness in LMICs.

Methods PubMed, Embase, Scopus, Cochrane CENTRAL, CINAHL, CNKI, PsycINFO and Web of Science including grey literatures and Google Scholar were systematically searched for randomised controlled trials (RCTs) and non-RCTs that evaluated the effect of SMS reminders on childhood immunisation and timeliness in LMICs. Risk of bias was assessed using the Cochrane Risk of Bias 2.0 assessment tool for RCTs and Cochrane Risk of Bias in Non-randomised Studies of Interventions tool for non-RCTs. Meta-analysis was conducted using random-effects models to generate pooled estimates of risk ratio (RR).

Results 18 studies, 13 RCTs and 5 non-RCTs involving 32 712 infants (17 135 in intervention groups and 15 577 in control groups) from 11 LMICs met inclusion criteria. Pooled estimates showed that SMS reminders significantly improved childhood immunisation coverage (RR=1.16; 95% CI: 1.10 to 1.21; I2=90.4%). Meta-analysis of 12 included studies involving 25 257 infants showed that SMS reminders significantly improved timely receipt of childhood vaccines (RR=1.21; 95% CI: 1.12 to 1.30; I2=87.3%). Subgroup analysis showed that SMS reminders are significantly more effective in raising childhood immunisation coverage in lower middle-income and low-income countries than in upper middle-income countries (p<0.001) and sending more than two SMS reminders significantly improves timely receipt of childhood vaccines than one or two SMS reminders (p=0.040).

Conclusion Current evidence from LMICs, although with significant heterogeneity, suggests that SMS reminders can contribute to achieving high and timely childhood immunisation coverage.

PROSPERO registration number CRD42021225843.

  • systematic review
  • vaccines
  • child health

Data availability statement

Extracted data are available, on request, from the corresponding author.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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Data availability statement

Extracted data are available, on request, from the corresponding author.

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  • Handling editor Seye Abimbola

  • Contributors PE and YA conceptualised the study and designed the protocol, with feedback from LOL. PE and LOL independently conducted the search, screening, data extraction, and assessment of bias and quality of reporting. PE conducted the meta-analysis and drafted the manuscript. LOL and YA reviewed the draft, provided critical review, and read and approved the final manuscript. The corresponding author, as guarantor, accepts full responsibility for the finished article, has access to the data and controlled the decision to publish. The corresponding author attests that all listed authors meet the authorship criteria and that no others meeting the criteria have been omitted.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.