Babies who have a strong immune reaction in the first week of life seem to have triple the risk of developing an allergy or eczema by age 1, compared with those who don’t. But the long-term impact of this early immune response, now defined for the first time, seems to be modulated by the microbiome and how babies are fed.
“If you ask 100 immunologists, they would say that immune development begins at birth and continuously develops over time, without discrete phases,” says Petter Brodin at Imperial College London.