Having a nasal microbiome dominated by bacteria of the genus Moraxella puts young children at increased risk of acute respiratory infections, according to the largest study in infants to date.

The Finnish study analysed nasal swabs from 839 healthy two-month-olds and followed the children until the age of two to see whether their nasal microbiome affected their risk of acute respiratory infection.

A total of 7810 episodes of respiratory infections were documented during the study period, with an incidence rate of 656 per 100 person-years.

However, the incidence varied between five distinct microbiota profiles (see below).