The introduction of newborn screening enables the detection of infants with severe combined immunodeficiency (SCID) before they become symptomatic, enabling definitive treatment before they acquire infection. Many states in the USA have now implemented newborn screening for SCID, and this study reports that 11 newborn screening programs identified SCID in 1 in 58,000 infants, and had a high survival rate. This Recommendation is of an article referenced in an F1000 Faculty Review also written by Andrew Gennery.