Relationship between nasopharyngeal microbiota and patient’s susceptibility to viral infection

ABSTRACT

Introduction: The burden of respiratory viral infections is a global public health concern with significant mortality, morbidity, and economic impact. While Koch’s postulate led to considering only the etiological agent, numerous works have demonstrated that commensal microbes could contribute to both the susceptibility and the severity of these infections, in particular those of the nasopharynx.

Areas covered: Herein, we first propose to briefly recall the historical background that led to considering microbes inhabiting the nasopharyngeal microbiota as a potential contributor to human viral infections. We describe the evolution of the normal nasopharyngeal microbiota composition over time, especially during the first year of life. We aimed to resume the changes of the nasopharyngeal microbiota during viral respiratory infections. We also develop how nasopharyngeal microbiota could contribute to the acquisition of respiratory viral infections. We finally provide the potential therapeutic perspectives deriving from these findings.

Expert opinion: Prospective studies focusing on children have identified that nasopharyngeal microbiota composition is associated with predisposition to acute respiratory illness and bronchiolitis, while data are scarce regarding adults. For the latter, further works are needed, in particular as a part of the multi-OMICS approach that should probably be performed in conjunction with gut microbiota studies.

KEYWORDS:

• Nasopharyngeal
• microbiota
• influenza
• RSV
• rhinovirus
• infections
• respiratory

Article highlights

• The nasopharyngeal microbiota is extremely dynamic, especially during the first year of life.

• There is a nasopharyngeal microbiota predisposing to acute respiratory diseases in children, particularly RSV infection.

• Due to an instability and seasonal variation, the nasopharyngeal microbiota of children is related to susceptibility to influenza.

• The presence of Haemophilus spp. is usually positively associated with both acquisition and severity of respiratory infections.

• Vaccination against pneumococcus significantly changes nasopharyngeal microbiota composition and substantially reduces incidence and severity of viral respiratory infections.

• There is currently little evidence on the use of probiotics to protect against viral respiratory infections.

• Prospective multi-OMICS studies, including sampling of different ecological niches, could lead to better understand host-microbes interactions in the context of viral respiratory infections.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This work has benefited from French State support, managed by the ‘Agence Nationale pour la Recherche’ including the ‘Programme d’Investissement d’avenir’ under the reference Méditerranée Infection 10-IAHU-03. This work was also supported by Région Provence Alpes Côte d’Azur and Fonds Européen de Développement Regional - Plateformes de Recherche et d’Innovation Mutualisées Méditerranée Infection (FEDER PRIMI).