Background Emerging evidence shows that airway microbiota may modulate local immune responses, thereby contributing to the susceptibility and severity of acute respiratory infections (ARIs). However, there are little data on the longitudinal relationships between airway microbiota and susceptibility to ARIs in children.
Objective We aimed to investigate the association of early nasal microbiota and the subsequent risk of ARIs during the first years of life.
Methods In this prospective population-based birth-cohort study in Finland, we followed 839 healthy infants for ARIs from birth to age 24 months. Nasal microbiota was tested using 16S rRNA gene sequencing at age 2 months. We applied an unsupervised clustering approach to identify early nasal microbiota profiles, and examined the association of profiles with the rate of ARIs during age 2–24 months.
Results We identified five nasal microbiota profiles dominated by Moraxella, Streptococcus, Dolosigranulum, Staphylococcus and Corynebacteriaceae, respectively. Incidence rate of ARIs was highest in children with an early Moraxella-dominant profile and lowest in those with a Corynebacteriaceae-dominant profile (738 vs 552/100 children years; unadjusted incidence rate ratio (IRR), 1.34; 95% CI 1.16 to 1.54; p < 0.001). After adjusting for nine potential confounders, the Moraxella-dominant profile-ARI association persisted (adjusted IRR (aIRR), 1.19; 95% CI 1.04 to 1.37; p = 0.01). Similarly, the incidence rate of lower respiratory tract infections (a subset of all ARIs) was significantly higher in children with an early Moraxella-dominant profile (aIRR, 2.79; 95% CI 1.04 to 8.09; p = 0.04).
Conclusion Moraxella-dominant nasal microbiota profile in early infancy was associated with an increased rate of ARIs during the first 2 years of life.
- lower respiratory tract infection
- nasal microbiota
- respiratory infections
- steps study
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Contributors LT collected the data, obtained the funding, carried out the statistical analysis, drafted the initial manuscript and approved the final manuscript as submitted. KH carried out the statistical analysis, reviewed and revised the initial manuscript, and approved the final manuscript as submitted. MW carried out the virological analysis and DNA extractions, reviewed and revised the manuscript, and approved the final manuscript as submitted. NA and JFP generated the microbiome data, carried out the initial statistical analysis, reviewed and revised the manuscript, and approved the final manuscript as submitted. CAC critically reviewed and revised the initial manuscript, and approved the final manuscript as submitted. VP conceptualised and designed the study, obtained the funding, supervised the conduct of the study, reviewed and revised the manuscript, and approved the final manuscript as submitted.
Funding This work was supported by the University of Turku; the Abo Akademi University; the Turku University Hospital; the Academy of Finland (Grant nos. 123571, 140251 and 277535); the Finnish Medical Foundation; the Päivikki and Sakari Sohlberg Foundation; the Foundation for Pediatric Research; Research Funds from Specified Government Transfers, Hospital District of Southwest Finland; the Foundation of the Finnish Anti-Tuberculosis Association; the Tampere Tuberculosis Foundation; the Allergy Research Foundation; the Emil Aaltonen foundation; the Maud Kuistila Memorial Foundation; the Orion Research Foundation; the Paulo Foundation; the Väinö and Laina Kivi Foundation and the Finnish Cultural Foundation.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The STEPS study was found ethically acceptable by the Ministry of Social Affairs and Health (STM 1575/2008, STM 1838/2009) and the Ethics Committee of the Hospital District of Southwest Finland (19.2.2008 §63, 15.4.2008 §134, 19.4.2011 §113).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data are available upon reasonable request.
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