Table 2.

Relationship between IgA in nasal fluid and shedding

Strain	Detectable viral shedding n (of 250)	Shed geomean (nasal IgA as % total: 95% CI)	Shed median (nasal IgA as % total)	No viral shedding n (of 250)	No shed geomean (nasal IgA as % total: 95% CI)	No shed median (nasal IgA as % total)	P‐value between Shed and no shed	Odds ratio (95% CI)*
H1N1	7	0·019 (0·007–0·053)	0·010	243	0·017 (0·015–0·02)	0·010	0·962	1·02 (0·65–1·61)
H3N2	49	0·051 (0·03–0·086)	0·030	201	0·048 (0·038–0·062)	0·027	0·892	1·01 (0·9–1·15)
B/Bris	89	0·012 (0·01–0·013)	0·010	160	0·011 (0·01–0·012)	0·010	0·985	1·02 (0·71–1·45)
B/Phu	71	0·055 (0·037–0·08)	0·033	178	0·071 (0·056–0·091)	0·060	0·279	0·92 (0·81–1·04)

Ig = immunoglobulin; CI = confidence interval; B/Phu = B Phuket strain; B/Bris = B Brisbane strain.

^*Odds of shedding per twofold change in antibody level adjusting for age and any previous influenza vaccine.