While previous studies have reported age-specific differences in neonatal adaptive immunity with a reduction in infant IFNγ responses to hepatitis B (27) or oral polio (28) vaccines as compared to vaccinated adults, BCG, or DNA vaccinations at birth have been shown to elicit strong T helper type 1 and CD8+ T cell responses during neonatal life (29–31). This evidence concerns the gene CD8A and poliomyelitis.