What is the right immunization to decrease a young child’s risk of ill health and slow learning? Adequate, healthy food. For 47 years American ingenuity has made that treatment efficiently available to millions of families through the Supplemental Nutrition Assistance Program (SNAP, formerly the Food Stamp Program), America’s strongest defense against hunger and food insecurity. About 50 percent of children in the United States are expected to live in households receiving SNAP at some point in their childhood. Protecting the availability and enhancing the dosage of this widely used pediatric “vaccine” should be a major public health priority. Children’s HealthWatch demonstrated that SNAP, like an effective immunization, significantly decreases families’ and children’s food insecurity, which are established child health hazards. Children’s HealthWatch also found that compared to young children in families that were likely eligible but not receiving SNAP, young children in families receiving SNAP were less likely to be underweight or at risk for developmental delays. When we specifically examined the impact of SNAP among young citizen children from immigrant families, those whose families received SNAP were more likely to be food secure and in better health than similar children whose immigrant families did not receive SNAP.