title: Mobile phone-delivered reminders and incentives to improve childhood immunisation coverage and timeliness in Kenya (M-SIMU): a cluster randomised controlled trial.
abstract: As mobile phone access continues to expand globally, opportunities exist to leverage these technologies to support demand for immunisation services and improve vaccine coverage. We aimed to assess whether short message service (SMS) reminders and monetary incentives can improve immunisation uptake in Kenya.
  
  
  
  In this cluster-randomised controlled trial, villages were randomly and evenly allocated to four groups: control, SMS only, SMS plus a 75 Kenya Shilling (KES) incentive, and SMS plus 200 KES (85 KES = USD$1). Caregivers were eligible if they had a child younger than 5 weeks who had not yet received a first dose of pentavalent vaccine. Participants in the intervention groups received SMS reminders before scheduled pentavalent and measles immunisation visits. Participants in incentive groups, additionally, received money if their child was timely immunised (immunisation within 2 weeks of the due date). Caregivers and interviewers were not masked. The proportion of fully immunised children (receiving BCG, three doses of polio vaccine, three doses of pentavalent vaccine, and measles vaccine) by 12 months of age constituted the primary outcome and was analysed with log-binomial regression and General Estimating Equations to account for correlation within clusters. This trial is registered with ClinicalTrials.gov, number NCT01878435.
  
  
  
  Between Oct 14, 2013, and Oct 17, 2014, we enrolled 2018 caregivers and their infants from 152 villages into the following four groups: control (n=489), SMS only (n=476), SMS plus 75 KES (n=562), and SMS plus 200 KES (n=491). Overall, 1375 (86%) of 1600 children who were successfully followed up achieved the primary outcome, full immunisation by 12 months of age (296 [82%] of 360 control participants, 332 [86%] of 388 SMS only participants, 383 [86%] of 446 SMS plus 75 KES participants, and 364 [90%] of 406 SMS plus 200 KES participants). Children in the SMS plus 200 KES group were significantly more likely to achieve full immunisation at 12 months of age (relative risk 1·09, 95% CI 1·02-1·16, p=0·014) than children in the control group.
  
  
  
  In a setting with high baseline immunisation coverage levels, SMS reminders coupled with incentives significantly improved immunisation coverage and timeliness. Given that global immunisation coverage levels have stagnated around 85%, the use of incentives might be one option to reach the remaining 15%.
  
  
  
  Bill & Melinda Gates Foundation.
authors.affiliation: International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: dgibso28@jhu.edu.
authors.forename: Dustin G
authors.initials: DG
authors.lastname: Gibson
authors.affiliation: Kenya Medical Research Institute/Centers for Disease Control and Prevention Public Health and Research Collaboration, Kisumu, Kenya.
authors.forename: Benard
authors.initials: B
authors.lastname: Ochieng
authors.affiliation: International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: E Wangeci
authors.initials: EW
authors.lastname: Kagucia
authors.affiliation: Kenya Medical Research Institute/Centers for Disease Control and Prevention Public Health and Research Collaboration, Kisumu, Kenya.
authors.forename: Joyce
authors.initials: J
authors.lastname: Were
authors.affiliation: International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Kyla
authors.initials: K
authors.lastname: Hayford
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Moulton
authors.affiliation: International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Orin S
authors.initials: OS
authors.lastname: Levine
authors.affiliation: Kenya Medical Research Institute/Centers for Disease Control and Prevention Public Health and Research Collaboration, Kisumu, Kenya.
authors.forename: Frank
authors.initials: F
authors.lastname: Odhiambo
authors.affiliation: International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: O'Brien
authors.affiliation: International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Feikin
mesh_terms: D040421:Cell Phone / Q000706:statistics & numerical data*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage*; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D007229:Infant Welfare / Q000706:statistics & numerical data*; D007231:Infant, Newborn; D007630:Kenya; D008297:Male; D010290:Parents / Q000193:education; D012052:Reimbursement, Incentive / Q000706:statistics & numerical data*; D017010:Reminder Systems / Q000706:statistics & numerical data*; D012424:Rural Population / Q000706:statistics & numerical data
chemical_list: D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; D017325:Hepatitis B Vaccines; C122182:diphtheria-tetanus-acellular pertussis-Hib-hepatitis B vaccine