
Bacteria have long been the star of microbiome research. But the human gut is not a monolithic place. The human microbiome includes bacteria, certainly, but also viruses — lots and lots of viruses, many of them benign.
And a new paper published Wednesday in Nature shows just how quickly viruses colonize a person’s “virome.” Within months of birth, an infant’s gut has already been colonized by two waves of viruses — some of which are linked to the common cold and noroviruses.