Effect of food coupon incentives on timely completion of DTP immunization series in children from a low-income area in Karachi, Pakistan: a longitudinal intervention study.

This study introduced food/medicine vouchers as an incentive to mothers of infants visiting Expanded Program on Immunization (EPI) centers in a low socio-economic area. The timely completion of diphtheria, tetanus and pertussis vaccines combined (DTP) series immunization rates between intervention and control cohorts were compared. The DTP up-to-date immunization coverage at 18 weeks of age increased two-fold (RR 2.20, 95% CI: 1.95-2.48, p<0.001) in the incentive cohort compared to the no-incentive cohort. While increasing immunization coverage is a complex structural and behavioral process, food/medicine coupon may improve routine immunization coverage in developing countries.