Systematic review investigating mHealth and digital health interventions for increasing vaccination uptake in 19 Sub-Saharan African countries: Recommendations for the malaria vaccine rollout

Abstract Mobile health and digital health (mHealth/DH) interventions have been shown to support immunisation programmes in Sub-Saharan Africa (SSA) and improve uptake of life-saving vaccines. As 19 SSA countries were targeted to begin rolling out the two new malaria vaccines (RTS,S/AS01 and R21/Matrix-M) in 2024, this systematic review aims to investigate which mHealth/DH interventions are most effective at increasing vaccination uptake (by assessing vaccination coverage and timeliness outcomes) in these 19 countries, and provide evidence-based recommendations on their use in the malaria vaccine rollouts. As the malaria and DTP/Pentavalent vaccines share the same mode of delivery and vaccination schedule, mHealth/DH interventions targeting increase of DTP/Pentavalent vaccines were investigated as predictors for the malaria vaccines. Eight electronic databases were searched, along with several grey literature sources. A narrative synthesis was conducted with studies being grouped together by mHealth/DH intervention-type. Included studies were assessed for risk of bias using RoB2 and ROBINS-I, and certainty of evidence for each outcome was evaluated using the GRADE approach. 14 studies were included, comprising both randomised and non-randomised control trials. However, only 4 out of the 19 SSA countries were represented (Nigeria, Kenya, Burkina Faso and Cote D’Ivoire). All investigated interventions were immunisation appointment reminders. Generally, all mHealth/DH intervention-type subgroups were positively associated with vaccination coverage and timeliness. SMS-based interventions showed modest positive associations between intervention and outcomes, whereas voice-based phone call reminders, reported the strongest associations. The certainty of evidence ranged from very low to moderate depending on the intervention-type and outcome pairing. While the findings suggest that implementing mHealth/DH interventions, particularly those with voice-based components, in this context would likely improve vaccination coverage and timeliness, the limited certainty of evidence highlights the need for further high-quality research. Based on the presented evidence, a combined SMS and voice-based intervention is recommended for the malaria vaccine rollouts. Competing Interest Statement The authors have declared no competing interest. Funding Statement The author(s) received no specific funding for this work. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability All relevant data are within the manuscript and its Supporting Information files.