Table 2.

Patient risk factors for hepatitis A acquisition and severe infection^*.

	n+	Percent (%)
History of Injection Drug Use N = 1372
No	1287	93.8
Yes	85	6.2
History of Substance Abuse N = 1214
None	747	61.5
Yes, active	241	19.9
Yes, not active	226	18.6
Male-to-male sexual contact N = 1372
No	855	62.3
Yes	517	37.7
Chronic HBV Infection1 N = 1372
No	1307	95.3
Yes	65	4.7
Chronic HCV Infection1 N = 1372
No	1331	97.0
Yes	41	3.0
History of Hemophilia1 N = 1372
No	1372	100

N = Total number of patients in sample, n⁺ = frequency.

HAV = hepatitis A virus.

¹by International Disease Classification (ICD-9) and ICD-10 codes, hepatitis B surface antigen and HCV RNA.

^*Excluding HIV, which was later added as a risk factor for HAV and indication for HAV vaccination[1].