The Impact of WIC on Infant Immunizations and Health Care Utilization.

OBJECTIVE

To test how prenatal participation in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) impacts health care utilization and immunizations within the first year of an infant's life.

DATA SOURCE

We utilize comprehensive South Carolina Medicaid claims data from 2004 to 2013 linked with birth certificates data from 2004 to 2012. These data contain information on WIC participation and all health care utilization within the first year of an infant's life.

STUDY DESIGN

We employ a maternal fixed-effects empirical design to control for unobserved factors that influence WIC participation and health care utilization.

PRINCIPAL FINDINGS

We estimate that WIC participation increases infant health care utilization within the first year of life by 0.20 well-child visits (95 percent CI 0.16-0.23), by 0.22 vaccinations (95 percent CI 0.17-0.27), and by increasing the probability of receiving care in an emergency room by 2.9 percentage points (95 percent CI 2.0-3.8). Additionally, our results show that WIC participation decreases the average number of days an infant spends in the hospital within his or her first year of life by 0.41 days (95 percent CI 0.22-0.60).

CONCLUSIONS

These findings suggest that WIC may increase health care costs in some dimensions while reducing it in others, and more work is needed to fully evaluate the impact of the program on future expenditures.