Differences in the severity and risk for COVID-19 infection observed between children, adolescents, and young adults may be associated with age-related changes of the nasopharyngeal microbiome, according to results of a study published in Clinical Infectious Diseases.
In this prospective cohort study, researchers assessed nasopharyngeal samples obtained from children, adolescents, and young adults. Samples were assessed to determine whether there is an association between changes that occur in the microbiome during infancy, childhood, and adolescence and SARS-CoV-2 susceptibility. Eligible patients included those with confirmed COVID-19 infection and those who were recently exposed to an individual with the infection. The researchers used linear regression models to determine the association between patient characteristics and both microbiome alpha diversity and nasopharyngeal microbiome composition. The association between patient characteristics and relative concentrations of specific bacterial genera within the nasopharyngeal micriobome were also evaluated.
A total of 285 patients were included in the study, of whom 74 (26%) were exposed but not infected with COVID-19, 98 (34%) were infected without respiratory symptoms, and 113 (40%) were infected with respiratory symptoms. Among patients positive for COVID-19 infection, those with respiratory symptoms were more likely to be older compared with those without respiratory symptoms (median age, 14.1 vs 9.3; P =.001). Patients with respiratory symptoms were also more likely to be older vs those who were exposed but not subsequently infected with COVID-19 (median age, 14.1 vs 9.5; P =.051). The researchers assessed patients’ microbiome composition and found that the risk for respiratory-related symptoms was decreased among those with Corynebacterium/Dolosigranulum-dominate microbiome profiles vs those with a microbiome profile dominated by other bacterial genera (odds ratio, 0.38; 95% CI, 0.18-0.81).
In regard to nasopharyngeal microbiome composition, the researchers found that 5 bacterial genera comprised more than 80% of those identified in swab samples, including Corynebacterium (26%), Staphylococcus (21%), Moraxella (15%), Dolosigranulum (13%), and Streptococcus (5%). In addition, an increased prevalence of Lawsonella and Peptoniphilus was observed in 78% and 69% of patients aged 12 years and older, respectively.
This study was limited by the inability to determine whether changes in microbiome compositions occurred prior to the onset of COVID-19 infection or were a consequence of infection, due to the collection of nasopharyngeal samples at a single timepoint. In addition, associations between microbiome composition and severe COVID-19 infection were not assessed because all patients had mild disease.
According to researchers, “[these] findings suggest that the upper respiratory microbiome may be a previously unrecognized and potentially modifiable mechanism by which age influences SARS-CoV-2 susceptibility and respiratory symptoms.”
Disclosure: Some authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Hurst JH, McCumber AW, Aquino JN, et al. Age-related changes in the nasopharyngeal microbiome are associated with SARS-CoV-2 infection and symptoms among children, adolescents, and young adults. Clin Infect Dis. Published online March 5, 2022. doi:10.1093/cid/ciac184