Table 3.

Subgroup Analyses for Clinical Influenza—the Full Analysis Set

Subgroup	LO-40SD			LO-20TD			Placebo
	No./Total (%)	P Valuea	RRRb (95% CI)	No./Total (%)	P Valuea	RRRb (95% CI)	No./Total (%)
Age
<16 y	1/33 (3.0)	.60	54.5 (–376.1 to 95.7)	1/35 (2.9)	.59	57.1 (–349.6 to 95.9)	2/30 (6.7)
≥16 y	11/234 (4.7)	.002	63.2 (28.3 to 81.1)	11/234 (4.7)	.002	63.2 (28.3 to 81.1)	30/235 (12.8)
Sex
Female	11/237 (4.6)	.001	63.6 (29.2 to 81.3)	11/241 (4.6)	.001	64.2 (30.3 to 81.7)	30/235 (12.8)
Male	1/30 (3.3)	1.00	50.0 (–422.4 to 95.2)	1/28 (3.6)	1.00	46.4 (–458.7 to 94.9)	2/30 (6.7)
Time from onset of influenza symptoms in the index patient to completion of the first study treatment
< 24 hours	10/180 (5.6)	.10	47.2 (−12.9 to 75.3)	4/159 (2.5)	.004	76.1 (30.1 to 91.8)	16/152 (10.5)
≥ 24 hours	2/87 (2.3)	.004	83.8 (31.3 to 96.2)	8/110 (7.3)	.13	48.6 (–15.1 to 77.1)	16/113 (14.2)
Vaccinated in current season
No	7/166 (4.2)	.01	63.6 (15.7 to 84.3)	3/168 (1.8)	<.001	84.6 (48.9 to 95.4)	19/164 (11.6)
Yes	5/101 (5.0)	.08	61.5 (–3.9 to 85.8)	9/101 (8.9)	.49	30.8 (–54.7 to 69.0)	13/101 (12.9)
Relationship to the index patient
Parent	11/223 (4.9)	.003	62.0 (26.1 to 80.5)	11/227 (4.8)	.002	62.7 (27.4 to 80.8)	30/231 (13.0)
Sibling	1/32 (3.1)	1.00	48.4 (–441.0 to 95.1)	1/37 (2.7)	.59	55.4 (–369.5 to 95.8)	2/33 (6.1)
Virus type and subtype
A/H1N1pdm09	0/0	–	–	0/1 (0.0)	–	–	0/1 (0.0)
A/H3N2	12/265 (4.5)	.001	63.5 (30.7 to 80.8)	12/258 (4.7)	.002	62.5 (28.8 to 80.2)	32/258 (12.4)
B	0/2 (0.0)	–	–	0/3 (0.0)	–	–	0/2 (0.0)
Negative	0/0	–	–	0/7 (0.0)	–	–	0/4 (0.0)

Abbreviations: CI, confidence interval; LO-20TD, 20 mg of laninamivir octanoate administered once daily for 2 days; LO-40SD, 40 mg of laninamivir octanoate, single administration; RRR, relative risk reduction.

^a Analyzed using Fisher exact test.

^b 100 × (1 − laninamivir/placebo).