de Koff EM, van Houten MA, Sanders EAM, et al. - Given that the clinical presentation of human coronavirus (HCoV) infections in children differs strongly, researchers assessed respiratory viruses and the nasopharyngeal bacterial microbiome in seasonal HCoV-associated lower respiratory tract infections (LRTI) in young children. It is shown that children with HCoV-associated LRTI were more likely to have respiratory syncytial virus codetected and a higher abundance of Haemophilus influenzae/haemolyticus than asymptomatic HCoV carriers and children with non-HCoV-associated LRTI. Symptomatology of HCoV-associated infections, including coronavirus disease 2019, can be driven by viral and bacterial cooccurrence.