Newborns treated with antibiotics respond less well to vaccines, study shows

The study of 191 newborns found those directly treated with antibiotics at birth had less of a group of beneficial gut bacteria known as Bifidobacterium. Photograph: Olena Malik/Getty Images

Babies who are treated with antibiotics as newborns have reduced immune responses to vaccines in later infancy, likely due to changes in the gut microbiome, new research suggests.

The Australian study tracked 191 healthy babies from birth, finding that those who received antibiotics in the first few weeks of life had significantly lower levels of antibodies against multiple vaccines at seven and 15 months.