Table 2. Assessment of Assisted Living Facility Resident Risk Factors for Hepatitis B Virus Infection, Virginia – March 2010.

Risk Factor	Acute Infections/Total Number		Risk Ratio
	at Risk for Acute Infection		(95% CI)†
	at Beginning of Outbreak* (%)
	Exposed	Unexposed
AMBG‡	12/13 (92)	2/75 (3)	35 (8.7, 137)
Injected medications	7/22 (32)	7/66 (11)	3.0 (1.2, 7.6)
AMBG‡ (+)	7/7 (100)	5/6 (83)	1.2 (0.8, 1.7)
AMBG‡ (−)	0/15 (0)	2/60 (3)	1.0 (0.98, 1.1)
Podiatry	9/39 (23)	5/49 (10)	2.3 (0.8, 6.2)
AMBG‡ (+)	8/9 (89)	4/4 (100)	0.9 (0.7, 1.1)
AMBG‡ (−)	1/30 (3)	1/45 (2)	1.5 (0.1, 23)

^*Uninfected and at risk for experiencing acute infection prior to the outbreak (i.e., subsequently determined by serologic testing to have become acutely infected or remained susceptible to infection).

^†Confidence interval.

^‡Assisted monitoring of blood glucose.