The goal of this interventional study is to learn about nasal microbiome and viral infections in newborns hospitalised in neonatology.

The main questions it aims to answer are :

• how often are newborns infected by viruses in neonatology ?
• how does the microbiome develop during first weeks of life ?
• how does microbiome and viruses interacts together ?
• is there a link between viral infection, microbiome, and medical complications during hospitalisation in neonatology ? Participants will have a nasal swab taken each week during their hospitalisation in neonatology, and researchers will take medical data from the medical chart.

Inclusion Criteria:

• newborn hospitalised in neonatal intensive care unit during the inclusion period
• parents have been informed about the study (speaking french) and have signed the informed consent.
• affiliated to the social security system.

Exclusion Criteria:

• parental refusal
• minor parents or under judicial protection
• newborn who already have been discharded home before inclusion
• hospitalisation after the first 48 hours of life
• only palliative care

Individual participant data will be anonymised.