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

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 DIvoire). 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.