Table 3. Crude and adjusted effectiveness of PPSV23 against hospitalization due to community-acquired pneumonia.

	Cases vaccinateda/N (%)	Controls vaccinateda/N (%)	Crude vaccine effectiveness(95% CI)	p-value	Adjusted vaccine effectiveness(95% CI)	p-value
All	259/1895 (13.7%)	272/1895 (14.4%)	5.8% (-13.7–21.9)	0.53	15.2% (-3.1–30.3)	0.10b
65–74 years	116/592 (19.6%)	133/592 (22.5%)	16.2% (-11.3–36.9)	0.22	23.6% (-3.0–43.3)	0.08c
75–84 years	94/879 (10.7%)	95/879 (10.8%)	1.2% (-34.5–27.5%)	0.94	11.5% (-22.1–35.9)	0.46d
≥85 years	49/424 (11.6%)	44/424 (10.4%)	-12.8% (-73.6–26.7)	0.58	0.3% (-57.7–36.9)	0.99e

^a In the 5 previous years. Adjusted for the propensity score.

Statistical power:

^b 41%,

^c46%,

^d12%,

^e3%