TABLE 3.

Geometric Mean and Protective Pneumococcal IgG Antibody Levels

	Entry			24 mo (Before PPV-23)			26 mo (After PPV-23)			Exit
	HU (n = 73)	Placebo (n = 69)	Pa	HU (n = 65)	Placebo (n = 58)	Pa	HU (n = 63)	Placebo (n = 56)	Pa	HU (n = 66)	Placebo (n = 62)	Pa
Serotype 26 (6B)
Geometric mean antibody (μg/mL)	7.4	7.2		6.9	5.4		37.9	46.6		9.4	9.6
95% CI	[5.7–9.5]	[5.7–9.2]		[5.1–9.3]	[4.2–7.0]		[29.6–48.6]	[35.3–61.4]		[7.6–11.7]	[7.6–12.0]
% Protective (≥1.0 μg/mL)	97.3	97.1	>.999	92.3	94.8	.721	100	100	—	100	100	—
95% CI	[90.5–99.7]	[89.9–99.7]		[83.0–97.5]	[85.6–98.9]		[94.3–100.0]	[93.6–100.0]		[94.6–100.0]	[94.2–100.0]
% Protective (≥0.35 μg/mL)	100.0	100.0	—	100.0	98.3	.471	100	100	—	100	100	—
95% CI	[95.1–100.0]	[94.8–100.0]		[94.5–100.0]	[90.8–100.0]		[94.3–100.0]	[93.6–100.0]		[94.6–100.0]	[94.2–100.0]
Serotype 51 (7F)
Geometric mean antibody (μg/mL)	1.2	1.0		1.5	1.2		8.4	9.4		3.7	3.2
95% CI	[1.0–1.5]	[ 0.8–1.2]		[1.2–1.9]	[0.9–1.5]		[6.4–11.0]	[7.2–12.2]		[3.0–4.5]	[2.6–3.9]
% Protective (≥1.0 μg/mL)	60.3	47.8	.177	72.3	58.6	.129	100	98.2	.47	90.9	93.5	.745
95% CI	[48.1–71.6]	[35.7–60.2]		[59.8–82.7]	[44.9–71.4]		[94.3–100.0]	[90.5–100.0]		[81.3–96.6]	[84.3–98.2]
% Protective (≥0.35 μg/mL)	91.8	85.5	.292	93.8	94.8	>.999	100	100	—	100	100	—
95% CI	[83.0–96.9]	[75.0–92.8]		[85.0–98.3]	[85.6–98.9]		[94.3–100.0]	[93.6–100.0]		[94.6–100.0]	[94.2–100.0]

CI, confidence interval; HU, hydroxyurea.

No P value calculated (—) when hydroxyurea and placebo % protected = 100%.

^aFisher’s exact test.