TABLE 1.

Demographic, Enrollment, and Risk Factor Characteristics of Vaccine Recipients: Vaccine Safety Datalink, 1996–2004

	Varicella Vaccine Recipients (n = 16 075)	Hepatitis A Vaccine Recipients (n = 594 917)	Hepatitis B Vaccine Recipients (n = 590 445)
Site, %
1	6	6	6
2	51	55	45
3	6	4	6
4	3	< 1	4
5	1	< 1	3
6	1	< 1	1
7	32	35	35
Age, %
2–4 y		27
5–8 y		15	15
9–12 y		19	44
13–17 y	73	17	26
18–29 y	13	4	4
30–49 y	14	8	7
50–64 y		7	3
≥ 65 y		3	1
Male, %	46	49	49
Years of continuous enrollment during study period, mean (range)
Before first dose	4.5 (1.0–11.9)	4.8 (1.0–12.0)	4.4 (1.0–12.0)
After first dose	4.2 (2.0–9.2)	3.8 (2.0–9.3)	5.1 (2.0–9.3)
Total	8.7 (3.0–14.1)	8.6 (3.0–14.1)	9.5 (3.0–14.1)
Year when first dose was received, %
1996	13	2	15
1997	15	4	22
1998	17	5	22
1999	17	6	19
2000	14	28	10
2001	13	30	7
2002	11	25	5
Any chronic condition, %	7	9	7
No. of medical visits in year prior to first dose
0	55	49	57
1–10	42	48	41
> 10	3	3	2