The role of ethnicity and travel on Hepatitis A vaccination coverage and disease incidence in Arizona at the United States–Mexico Border

Figures & data

Figure 1. Relative incidence of hepatitis A, 2006–2010: Arizona, United States, Sonora, and Mexico.

Table 1. Descriptive statistics of hepatitis A cases reported 2006–2011, Arizona

		Number of cases (%)	Rate / 100 000 population	Relative Risk (95% Confidence interval)
Region	Border	193 (31%)	2.33	1.64 (1.45, 1.84)*
	Non-border	432 (69%)	1.42	Reference
Year reported	2006	179 (29%)	2.87	Reference
	2007	143 (23%)	2.22	0.77 (0.66, 0.91)*
	2008	115 (18%)	1.76	0.61 (0.52, 0.72)*
	2009	67 (11%)	1.02	0.35 (0.29, 0.43)*
	2010	61 (10%)	0.95	0.33 (0.27, 0.41)*
	2011	60 (10%)	0.93	0.32 (0.26, 0.40)*
Race/ethnicity	White, non-Hispanic	224 (36%)	0.97	Reference
	Hispanic	215 (34%)	1.99	2.05 (1.79, 2.34)*
	Other: Total	48 (8%)	1.04	1.07 (0.86, 1.31)
	• Asian	14 (2%)	1.31	1.07 (0.93, 1.83)
	• African American	9 (1%)	0.58	0.60 (0.37, 0.85)*
	• American Indian	23 (4%)	1.14	1.18 (0.87, 1.52)
	• Other	2 (0.3%)	N/A	N/A
	Unknown	138 (22%)	N/A	N/A
Age Mean = 35.4 (95% CI 34–37) Median = 32	<1 y	6 (1%)	1.06	1.08 (0.56, 1.78)
	1–4 y	9 (1%)	0.39	0.39 (0.23, 0.61)*
	5–14 y	70 (11%)	1.27	1.30 (1.00, 1.70)
	15–24 y	142 (23%)	2.63	2.68 (2.15, 3.39) *
	25–64 y	347 (56%)	1.76	1.80 (1.49, 2.21) *
	≥65 y	50 (8%)	0.98	Reference
Sex	Female	303 (48%)	1.57	Reference
	Male	321 (51%)	1.66	1.06 (0.95, 1.19)

* Indicates a significant difference in population rates compared with the reference group for CI not including a null value of 1.

Figure 2. One-dose coverage with hepatitis A vaccine, Arizona, 2006–2011, by age group and region (border and non-border).

Table 2. Comparison of hepatitis A cases and risk factors for cases in the border region and non-border region, 2006–2011, Arizona

		Arizona n = 625	Border Region n = 193	Non-border Region n = 432	p-value for chi-square test^†
Race/ethnicity	White, non-Hispanic	224 (36%)	55 (29%)	169 (39%)	P < 0.0001*
	Hispanic	215 (34%)	110 (57%)	105 (24%)
	Other	46 (7%)	6 (3%)	40 (9%)
	Unknown	140 (22%)	22 (11%)	118 (27%)
Age: mean (95% CI); median		35.4 (33.9–36.9); 32	32.5 (29.6–35.4); 28	36.7 (34.9–38.5); 35	P value for t test = 0.01*
Age group	<1 y	6 (1%)	0 (0%)	6 (1%)	P = 0.001*
	1–4 y	9 (1%)	5 (3%)	4 (1%)
	5–14 y	70 (11%)	35 (18%)	35 (8%)
	15–24 y	142 (23%)	43 (22%)	99 (23%)
	25–64 y	347 (56%)	93 (48%)	254 (59%)
	65+ years	50 (8%)	17 (9%)	33 (8%)
Risk factor data available		450 (72%)	169 (88%)	281 (65%)	P < 0.0001*
International travel	Yes	229 (51%)	95 (56%)	134 (48%)	P = 0.11
	No	197 (44%)	67 (40%)	130 (46%)
	Unknown	24 (5%)	7 (4%)	17 (6%)
Daycare employment, attendance, or contact	Yes	26 (6%)	12 (7%)	14 (5%)	P = 0.38
	No	411 (91%)	154 (91%)	257 (91%)
	Unknown	13 (3%)	3 (2%)	10 (4%)
Sexual or household contact with hepatitis A case	Yes	37 (8%)	7 (4%)	30 (11%)	P = 0.01*
	No	301 (67%)	122 (72%)	179 (64%)
	Unknown	112 (25%)	40 (24%)	72 (24%)
Men who had sex with men (includes men only)	Yes	16 (7%)	2 (2%)	14 (9%)	P = 0.07
	No	122 (52%)	43 (49%)	79 (53%)
	Unknown	98 (42%)	42 (48%)	56 (38%)
Injecting drug use	Yes	10 (2%)	1 (1%)	9 (3%)	P = 0.05
	No	349 (78%)	145 (86%)	204 (73%)
	Unknown	91 (20%)	23 (14%)	68 (24%)
Foodborne outbreak	Yes	10 (2%)	0 (0%)	10 (4%)	P = 0.01 *
	No	297 (66%)	127 (75%)	170 (61%)
	Unknown	143 (32%)	42 (25%)	101 (36%)
Number of risk factors identified	None	158 (35%)	62 (37%)	96 (34%)	P = 0.80
	1	256 (57%)	96 (57%)	160 (57%)
	2	32 (7%)	10 (6%)	22 (8%)
	3	4 (1%)	1 (1%)	3 (1%)

^† Chi-square tests for differences in proportions compare Border to Non-Border regions. “Unknown” answers are excluded from the chi-square analysis. *Indicates a significant difference between proportions in the border and non-border regions at α = 0.05.

Table 3. Comparison of hepatitis A cases reporting international travel (n = 229) in the border region and non-border region, 2006–2011, Arizona

		Arizona n = 229	Border Region n = 95	Non-border Region n = 134	P value for chi-square test^†
Travel location	Mexico/South-Central America	196 (86%)	89 (94%)	107 (80%)	P = 0.01*
	Other	28 (12%)	6 (6%)	22 (16%)
	Unknown	5 (2%)	0 (0%)	5 (4%)
Race/ethnicity	White, non-Hispanic	75 (33%)	19 (20%)	56 (42%)	P = 0.0003*
	Hispanic	121 (53%)	65 (68%)	56 (42%)
	Other	10 (4%)	3 (3%)	7 (5%)
	Unknown	23 (10%)	8 (8%)	15 (11%)
Age: mean (95% CI); median		29.0 (26.8, 31.2); 25	26.8 (23.4–30.3); 24	30.6 (27.7–33.5); 27	P value for t test = 0.10
Additional risk factors	None	198 (86%)	85 (89%)	113 (84%)	P = 0.51
	1	27 (12%)	9 (9%)	18 (13%)
	2	4 (2%)	1 (1%)	3 (2%)

^† Chi-square tests for differences in proportions compare border to non-border regions. “Unknown” answers are excluded from the chi-square analysis. *Indicates a significant difference between proportions in the border and non-border regions at α = 0.05.