Newborns’ weak immunity may allow helpful bacteria to gain a foothold

Though infant immune systems raise risk of infection, they also allow good microbes into the body

GROWING GOOD BACTERIA  An immature form of red blood cell helps suppress the immune system of newborns, experiments with mice suggest. Immune suppression leaves infant mice and humans susceptible to infection but may allow good bacteria to settle in the gut.

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The seeming failure of newborns to muster a robust defense against infections is a trade-off that delivers long-term benefits, a new study suggests.