Combating Viral Susceptibility in Premature Infants

We are studying how the communities of bacteria and viruses that live in the nose and gut— the “microbiome”—influence respiratory infections in babies. To do this, we followed a group of preterm and full-term infants, and we also included adults who had respiratory infections for comparison. We found that the mix of microbes in the nose changes during a respiratory infection, and that these patterns look different across people. We also saw that, after birth, the nose and gut microbiome change rapidly as babies grow and encounter new environments, foods, and everyday exposures. To understand how the body reacts to these microbes, we measured many parts of the nasal immune response (using several “omics” tools that let us look broadly at genes and immune signals). Preterm babies’ nasal cells responded differently from those of full-term infants and adults, tending to show stronger inflammation and to call in more immune cells. Finally, we recreated parts of these interactions in the lab by growing common bacteria and viruses together with human immune cells. This helped us pinpoint specific microbes that can trigger excessive inflammation in the airways. Taken together, early-life microbes in the nose and gut are constantly changing and can strongly shape immune responses—especially in preterm infants—helping explain why some babies are more vulnerable to breathing problems and pointing to new ways to prevent or calm harmful inflammation.