RESUMEN
OBJECTIVES: Young children in resource-poor settings remain inadequately immunized. We evaluated the role of compliance-linked incentives versus mobile phone messaging to improve childhood immunizations. METHODS: Children aged ≤24 months from a rural community in India were randomly assigned to either a control group or 1 of 2 study groups. A cloud-based, biometric-linked software platform was used for positive identification, record keeping for all groups, and delivery of automated mobile phone reminders with or without compliance-linked incentives (Indian rupee Rs30 or US dollar $0.50 of phone talk time) for the study groups. Immunization coverage was analyzed by using multivariable Poisson regression. RESULTS: Between July 11, 2016, and July 20, 2017, 608 children were randomly assigned to the study groups. Five hundred and forty-nine (90.3%) children fulfilled eligibility criteria, with a median age of 5 months; 51.4% were girls, 83.6% of their mothers had no schooling, and they were in the study for a median duration of 292 days. Median immunization coverage at enrollment was 33% in all groups and increased to 41.7% (interquartile range [IQR]: 23.1%-69.2%), 40.1% (IQR: 30.8%-69.2%), and 50.0% (IQR: 30.8%-76.9%) by the end of the study in the control group, the group with mobile phone reminders, and the compliance-linked incentives group, respectively. The administration of compliance-linked incentives was independently associated with improvement in immunization coverage and a modest increase in timeliness of immunizations. CONCLUSIONS: Compliance-linked incentives are an important intervention for improving the coverage and timeliness of immunizations in young children in resource-poor settings.