Table 2.

Unadjusted VE of PPV23 vaccination against pneumococcal diseases among people aged 60 years or older.

	a	b	c	d	Crude VE, % (95%CI)	P
Total	70	166	217	753	24 (2, 40)	0.035
Stratified by gender
Male	58	130	155	597	16 (−12, 37)	0.236
Female	12	36	62	156	44 (6, 67)	0.030

^aNumber of pairs that subjects in case and control groups were both vaccinated.

^bNumber of pairs that subjects in case group was vaccinated but not in control group.

^cNumber of pairs that subjects in control group was vaccinated but not in case group.

^dNumber of pairs that subjects in control and case groups were both not vaccinated.