A Status Report from 1996–2004: Are More Effective Immunization Interventions Being Used in the Women, Infants, and Children (WIC) Program?

Background: The Special Supplemental Nutrition Program for Women, Infants and Children (WIC) enrolls almost 50% of the US birth cohort and these children have significantly lower immunization coverage rates than their counterparts not eligible for WIC. In 1994, the Centers for Disease Control and Prevention (CDC) and USDA began a national initiative to increase immunization coverage in low-income children by incorporating immunization-promoting activities into WIC visits (WIC/Immunization linkages). Since 1998, CDC has monitored the WIC/Immunization linkages assessment and referral (with and without the more aggressive strategy of monthly voucher pick-up, client outreach and tracking and parental incentives) and three other immunization supporting activities (computerized systems to assess immunization status, collocation of WIC and immunization services, coordination of WIC and immunization services).

Methods: Through an annual survey of state Immunization and WIC programs, a trend analysis was conducted for years 1998 through 2004 to determine changes in the use and frequency of WIC/Immunization linkage activities.

Results: During the 7-year study period, the use of assessment and referral increased from 71% to 94%, monthly voucher pick-up from 24% to 35%, and coordination of WIC and immunization services from 61% to 78% (p<0.0001 for all comparisons) in WIC sites nationwide. The frequency of assessment and referral (at each visit [four or more times/ year] versus certification visits [two times/year]) was reported to decrease during the study period (p<0.0001). Outreach and tracking and collocation of services did not change significantly while the use of parental incentives decreased (p<0.0001). The availability of computers and their use immunization assessment increased during the period. From 2002-2004, the number of states reporting that they base assessment and referral on a single vaccine (diphtheria-tetanus-acellular pertussis) instead of counting multiple vaccines increased from 5 to 10.

Conclusions: Immunization promoting activities, especially those known to be most effective in improving coverage such as monthly voucher pickup, are increasing in WIC. Focusing on effective interventions including supporting activities such as computerized assessment will be essential in meeting Healthy People 2010 infant and childhood immunization coverage goals. In addition, the use of WIC resources can be minimized by encouraging evaluation of diphtheria-tetanus-acellular pertussis coverage as a marker for up to date status, instead of counting all vaccine doses.