Persistence of hepatitis B vaccine immune protection and response to hepatitis B booster immunization

Table 1 Positive rates for anti-HBs, anti-HBc and HBsAg of 1018 children aged 1-7 years after infancy hepatitis B immunization in Longan County in 1994

Age group (yr)	No. of subjects	Anti-HBs (≥ 10S/N)		Anti-HBc (≥ 75%)		HBsAg (≥ 2.1S/N)
		n	%	n	%	n	%
1-2	220	165	75.0	1	0.5	2	0.9
3-4	341	178	52.2	13	3.8	9	2.6
5-6	320	144	45.0	8	2.5	7	2.2
7	137	66	48.2	8	5.8	1	0.7
Total	1018	553	54.3	30	3.0	19	1.9

Table 2 Comparison of anti-HBs level before and after hepatitis B booster in 144 subjects immunized with hepatitis B vaccine

Time point of observation	No. of subjects	Anti-HBs (mIU/mL)
		< 10		≥ 10		≥ 100		≥ 1000		GMT	t	P
		n	%	n	%	n	%	n	%
Before booster	144	65	45.1	58	40.3	20	13.9	1	0.7	10.4
One month after booster	144	15	10.4	16	11.1	100	69.4	13	9.0	190.6	17.4	< 0.01
12 months after booster	106*	26	24.5	43	40.6	33	31.1	4	3.8	25.3	1.3	> 0.05

^* blood specimens only collected from 106 children in the 12th month after booster.

Table 3 Distribution of anti-HBs levels one and twelve months after booster among immunized children with different anti-HBs levels before booster

Anti-HBs (mIU/ml) before booster	Anti-HBs levels (mIU/mL) one month after booster									Anti-HBs levels (mIU/mL) 12 months after booster
	No.	< 10		≥ 10		≥ 100		≥ 1000		No.	< 10		≥ 10		≥ 100		≥ 1000
		n	%	n	%	n	%	n	%		n	%	n	%	n	%	n	%
< 10	65	15	23.1	10	15.4	35	53.9	5	7.7	47	22	46.8	14	29.8	9	19.1	2	4.3
≥ 10	58	0	0.0	5	8.6	49	84.5	4	6.9	45	4	8.9	24	53.4	15	33.3	2	4.4
≥ 100	20	0	0.0	1	5.0	15	75.0	4	20.0	13	0	0.0	5	38.5	8	61.5	0	0.0
≥ 1000	1	0	0.0	0	0.0	1	100.0	0	0.0	0	0	0.0	0	0.0	1	100.0	0	0.0