Table 2.

Non-response rates of infants with different PVST intervals

PVST interval (month) after the third dose vaccine	Rate of non-responders (%)	Statistical analysis (χ2)	P
1–	3/191 (1.6)*	–	–
2–	3/278 (1.1)	0.213	0.645
3–	2/220 (0.9)	0.372	0.542
4–	1/141 (0.7)	0.537	0.464
5–	1/95 (1.1)	0.130	0.719
6–	1/136 (0.7)	0.488	0.485
7–8	11/194 (5.7)	4.616	0.032

*Reference variable.