THE IMMUNIZATION OF CHILDREN ENROLLED IN THE SPECIAL SUPPLEMENTAL FOOD PROGRAM FOR WOMEN, INFANTS, AND CHILDREN (WIC) - THE IMPACT OF DIFFERENT STRATEGIES

Objective.-To assess the impact of different interventions to increase measles vaccination coverage among preschool children enrolled in the Special Supplemental Food Program for Women, Infants, and Children (WIC). Design.-Public health intervention trial. Setting.-Six volunteer WIC sites in New York City. Study Participants.-Children aged 12 to 59 months presenting for WIC certification between April 1 and September 30, 1991, who were eligible for measles vaccination. Interventions.-Two WIC sites were assigned at random to one of three immunization strategies: (1) escort: child was escorted to a nearby pediatric clinic for immunization; (2) voucher incentive: the family returned monthly, rather than every 2 months, to pick up WIC food vouchers until the child was immunized; or (3) referral: the family was passively referred for immunization. Main Outcome Measure.-Proportion of eligible children receiving measles vaccination. Results.-Of children eligible for measles immunization, 74% (618/836) were immunized. Children at escort sites were 5.5 times (relative risk [RR]=5.5; 95% confidence interval [CI], 3.7 to 8.1) and those at voucher incentive sites were 2.9 times (RR=2.9; 95% CI, 1,9 to 4.5) more likely to be immunized than children at referral sites. Children were immunized more rapidly at escort sites (median, 14 days) and voucher incentive sites (median, 26 days) than at referral sites (median, 45 days; P<.001). Conclusions.-Both escort and voucher incentive models resulted in more children being immunized more rapidly than passive referral. Because of ease of administration, voucher incentives may be a more suitable immunization intervention for use at WIC sites, with addition of escort where feasible.