Mobile Health Interventions on Vaccination Coverage among Children under 5 Years of Age in Low and Middle-Income Countries; a Scoping Review

"The impact of this study is that it could inform policymakers and practitioners in LMIC[s - low- and middle-income countries] that adopting the use of mHealth may be a low hanging fruit in improving vaccination coverage in their countries."

Low- and middle-incoume countries (LMICs) are increasingly using mHealth, which includes the use of applications and technologies such as voice and text messaging (short message service, or SMS), and multimedia message services. Recent evidence about the use of mHealth applications to facilitate vaccine uptake has resulted in questions about how effective these approaches are in LMICs. The aim of this study was to synthesise evidence concerning the context, mechanisms, and outcome elements of mobile health interventions in improving vaccination coverage among children under 5 years of age in LMICs.

A search conducted using PubMed, Web of Science, ScienceDirect, CINAHL, Embase, and the Cochrane library led to 27 studies included in the final analysis (out of 357 identified articles). There were 18 randomised controlled trials (RCT), 3 quasi-experimental studies, and 3 intervention studies. In addition, there were 2 cross-sectional/descriptive studies and 1 prospective controlled evaluation study. Twenty-one studies were from Africa, 4 from Asia, and 2 from Latin America and the Caribbean.

Most of the RCT studies reported the use of phone calls or SMS reminders to increase vaccination coverage. Three of these studies (2 in Kenya and 1 in Nigeria) included monetary incentives to increase coverage among participants. Twenty-one of the studies were conducted on SMS vaccine reminders in Africa, out of which 18 revealed either an increase in vaccination coverage, decrease in dropout rates, increase in completion rate, or a decrease in delayed vaccination. Six studies focused on SMS reminder systems as an intervention, with no reminder system as the control. However, 4 studies added other forms of intervention alongside SMS reminders.

A Zimbabwean RCT showed that immunisation coverage and adherence to immunisation schedule was higher among those in the SMS intervention group in comparison with the control group. SMS reminders were sent to parents (n = 152) when their baby was 6, 10, and 14 weeks old, in addition to routine health education. The control group received health education alone (n = 152). At all 3 time points, the percentage of children fully vaccinated with the relevant dose of polio, pentavalent, and pneumococcal vaccines was significantly higher in the intervention group compared to the control group (p < 0.001), and the delay in receiving the vaccinations was significantly less in the intervention group compared to the control group (p < 0.001).

Three studies involved systematic reviews and meta-analysis conducted in multiple countries in Asia, Africa, and the Americas. All the studies reported positive changes in the vaccinated coverage and output of vaccination programmes in LMICs. he most prominent effect was found in a systematic review of 13 RCTs and 5 non-RCTs in which pooled estimates showed that SMS reminders significantly improved childhood immunisation coverage.

Non-RCT studies also indicated favourable vaccination uptake results. For example, a random sampling with SMS-based monitoring of child immunisation to ask the caregivers whether their children received vaccines concluded that SMS was an effective strategy to monitor coverage following mass immunisation.

Overall, SMS reminders for vaccination appointments were found to increase vaccination uptake and reduce delays in receiving vaccinations with a direct association in all but two of the studies. In certain instances, monetary incentives proved beneficial, as mothers who received an incentive reported mostly positive experiences with receiving SMS reminders about vaccination appointments.

The researchers observed that education and behavioural change because of mHealth interventions was the most represented domain, to which 21 of the reviewed papers related. Mobile technology makes it easier to contact individuals and offers a tool to deliver education and improve health-seeking behaviour or health-related lifestyle decisions. However, there was no qualitative study in the review to explore other factors that may have been responsible for any observed change.

One interesting point for consideration is the possibility for interventions with mixed information delivery modes to have an enhanced effect. In this review, interventions that combined texting and phone calls all reported improved results. In addition, although little was reported about the processes of development of the mHealth messages, there is potential to increase community participation and overall interest in vaccination among mothers and caregivers during the development process, especially if it involves development and pilot testing phases.

In conclusion: "The results from most studies suggest an improved uptake of vaccination with mobile health interventions. However, there is a need for further research to quantify the impact of these interventions and determine the most effective strategies."