Sample collection from 50 human subjects.

Three swabs (nasal, oropharyngeal, and nasopharyngeal) were collected from each volunteer (subject numbers 14–63) during each of two visits (1/2) in every quarter (i.e., S1–S4). Green diamond symbols show swab collection dates. Red bars denote flu shot vaccination dates (26 subjects). Black bars denote Flu Mist vaccination dates (19 subjects). The dots on the X-axis filled in with color show musician types: Empty, non-musician (11); Green, pianist or conductor (2); Purple, percussionist (5); Cyan, vocalist (4); Yellow, violinist (3); Gray, wind instrumentalist (25).