[Correspondence] Beyond bacteria: a multikingdom ecological perspective on neonatal gut and severe viral lower respiratory tract infection risk

We commend Cristina Garcia-Mauriño and colleagues for their Article published in The Lancet Microbe linking a Bifidobacterium longum-dominated gut microbiota to a reduced risk of severe viral lower respiratory tract infections.1 Although their work provides a valuable foundation for understanding the early-life gut–lung axis, Garcia-Mauriño and colleagues exclusively focused on bacteria. The neonatal gut is a complex habitat in which bacteria, viruses (notably bacteriophages), and fungi interact to collectively shape host immunity.