Salk, Hannah M.

Abstract Pre and post-licensure studies have supported the safety of the intranasally administered live, attenuated influenza vaccine (LAIV). The objective of this study was to measure changes to the nasal microbiome in subjects who received LAIV. We hypothesized that administration would result in only a transient alteration of the nasal microbiome. To test this hypothesis, we swabbed the anterior nares just before vaccination (Day 0), and on Day 7 and Day 28. We performed next-generation sequencing on amplified 16s rRNA genes. There was a significant increase in alpha diversity (Observed, CHAO, and ACE) from Days 0 to 7 (p = 0.02, 0.00, 0.01; respectively) and Days 0 to 28 (p = 0.05, 0.03, 0.05; respectively). When measuring differences in specific observed taxanomic units (OTUs), we identified a significant increase in Flavobacteriaceae and Enterobacteriaceae after vaccination. These data suggest that LAIV may increase the ability of these less abundant OTUs to establish a community niche and, therefore, could be clinically relevant. We have begun to investigate the second objective of this study, which is to correlate microbiome composition with mucosal immunity to influenza virus. To our knowledge, this is the first study to investigate LAIV-induced alterations to the human microbiome. These data may lead to a better understanding of the influences of the host microbiome on the response to vaccine, and perhaps infection.