Does reminder-recall augment the impact of voucher incentives on immunization rates among inner-city infants enrolled in WIC?

Inner-city infants (n = 565) enrolled in the WIC program were randomly assi gned at 6 months of age to either of 2 groups: (1) voucher incentive (frequ ency of issuance of food vouchers based on immunization status) plus remind er-recall (calls and/or letters to families of under-vaccinated children) o r (2) voucher incentive alone. At 12 months, both groups' immunization leve ls were high and not significantly different: 80% +/- 4% versus 79% +/- 5% (P = .749).