SMS-based interventions for improving child and adolescent vaccine coverage and timeliness: a systematic review

This systematic review examined 30 randomised trials to assess whether SMS text message reminders help improve vaccination rates and timeliness in children and adolescents under 18 years old. SMS-based interventions showed small to moderate improvements in vaccine coverage compared to no reminder. Reminders that included educational content or were paired with financial incentives worked better than simple reminder messages. Most studies were conducted in high-income countries, and there was considerable variation in how effective the interventions were across different settings.

Key points

• 30 randomised trials were included in the systematic review, with most conducted in high-income countries
• SMS-based interventions were associated with small to moderate improvements in vaccine coverage and timeliness
• Reminders combined with embedded education or monetary incentives performed better than simple reminders in some settings
• Marked heterogeneity between studies limits the ability to draw uniform conclusions
• The review identifies message content and timing as key factors that need further investigation

Limitations

The review does not provide detailed information about which specific settings or populations benefited most from SMS interventions, nor does it clarify what constitutes 'small to moderate' improvements in quantitative terms. The high heterogeneity between studies suggests that effectiveness may vary substantially depending on context, making it difficult to generalise findings across different countries and healthcare systems.