The BEGIN Study Bifidobacterium Infantis to Newborns: Effects of Modulating the Gut Microbial Composition on Growth, Immune Function and Inflammatory Conditions - a Randomized Placebo-controlled Double-blinded Intervention Trial

The goal of The BEGIN Study, a randomized controlled double-blinded intervention trial, is to learn if probiotics, with Bifidobacterium longum subspecies infantis Bifin02 (B. infantis), given to healthy newborns can affect various health outcomes and to explore impacts of the infant gastrointestinal microbiome. The main questions it aims to answer are: * Does B. infantis probiotics impact immune function and does it lower the number of bacterial infections and use of antibiotics? * Does B. infantis probiotics impact overall health, development, growth and wellbeing? * Does B. infantis probiotics impact inflammatory diseases, allergies and autoimmune diseases Researchers will compare B. infantis probiotics to a placebo (a look-alike substance that contains no probiotic) to see if B. infantis colonization impact the human immunesystem and various clinical and biochemical health markers. Participants (parents) will * Orally administrate the B. infantis probiotic to their newborn child daily in three weeks from 7 days of age. * Answer baseline and follow up questionnaires in a study app * Take five stool samples from the child and one stool sample from the mother * Collect a 4 week of passive dust sample at home (Electrostatic Dust fall Collector) * Donate one dried bloodspot and one blood sample from their child