Newborns' immune systems are not immature, according to new research. Children use the immune system differently than adults, but efficiently.
Adult T cells outperform newborn T cells in tasks such as recognizing antigens, forming immunological memory, and responding to repeated infections. While adult immunity uses adaptive immunity - recognizing specific germs and then fighting them later - newborn immunity is activated by proteins associated with innate immunity, which offers rapid but non-specific protection against microbes that the body he has never met.