Table 2.

Age-specific incidence (cases per thousand) of herpes zoster and trends, Massachusetts, 1999–2003

Year	Parameter	Age group in years
		1–24	25–44	45–64	65+	All ages, crude	All ages, standardized a
1999
	nb	5655	4230	2214	911	13010
	Cases	5	14	11	10	40
	Incidence	0.87	1.87	4.82	6.9	2.23	2.77
	95% CI	0.25–3.05	0.90–3.88	2.36–9.86	2.97–16.05	1.46–3.43	1.82–4.20
2000
	nb	3668	3449	2211	1121	10449
	Cases	2	12	13	8	35
	Incidence	0.46	3.74	6.45	6.45	3.57	3.54
	95% CI	0.11–1.91	2.04–6.76	3.60–11.29	3.04–13.16	2.50–5.08	2.48–5.03
2002
	nb	3469	3234	2451	1303	10457
	Cases	6	14	20	23	63
	Incidence	1.70	5.13	7.42	20.03	6.51	6.47
	95% CI	0.71–4.03	2.65–9.70	4.39–12.28	12.46–30.59	4.86–8.67	4.92–8.47
2003
	nb	3698	3260	2700	1278	10936
	Cases	8	16	18	14	56
	Incidence	2.19	4.88	6.79	11.74	5.38	5.25
	95% CI	1.05–4.50	2.86–8.20	4.02–11.23	6.57–20.12	4.03–7.14	3.96–6.94
1999–2003
	% change for period	152%	161%	41%	70%	141%	90%
	p for trend test	0.10	0.03	0.42	0.03	0.0001	0.0009

^a Incidence is standardized using the standard 2000 U.S. population. The p-value is from age-adjusted analysis for trend using logistic regression.

^b N's exclude individuals for whom age or herpes zoster status was missing. The number excluded for these reasons was 1011, 513, 887, and 506 in 1999, 2000, 2002, and 2003, respectively. Values for n's and numbers of cases are unweighted, whereas incidence rates and 95% confidence intervals are based on weighted analysis.