A hepatitis B virus infection outbreak among residents and staff of an assisted living facility - Virginia, 2009

Background: In 2009, 5 older adults with hepatitis B virus (HBV) infection were reported to the local health department. Four had resided and 1 worked at the same assisted living facility in Virginia; none reported HBV-related risk behaviors or exposures.

Objective: To investigate and determine the source, magnitude and mode of HBV transmission and prevent further infections.

Methods: A public health response team was organized to coordinate the outbreak investigation. A facility inspection was made to assess resident care and staff infection control (IC) practices. Blood was drawn from current residents and facility staff to determine HBV infection status. Data on resident demographics and potential HBV exposures were collected and compared using odds ratios or the Kruskal-Wallis rank test.

Results: Among 47 current residents, median age was 83 years (range 59-95), 19% were male, and 83% were black. HBV status was determined for 44 (94%) residents, and 15 (88%) of 17 staff. Among residents, 27 were susceptible, 7 had past HBV infection, and 10 had acute or chronic HBV infection (Table). Among staff, 2 had acute and 1 had chronic HBV infection. Only 2 staff reported receipt of hepatitis B (HB) vaccine; it was not offered upon hire.  During inspection and observation of practices, there was no evidence of resident risk behaviors or abuse. The (HBV susceptible) podiatrist did not adequately clean and disinfect instruments. No IC breaches during diabetes care practices were identified. However, having diabetes and undergoing blood glucose monitoring were significantly associated with acute and chronic HBV infection; podiatry was not (Table). Both staff with acute HBV infection performed blood glucose monitoring and insulin injections. Facility IC practices were reinforced and HB vaccine administered to susceptible residents and staff.

Table: Resident demographics and potential exposures by HBV infection status
	HBV susceptible n=27	Active infection (HBsAg+)		P-value or Odds Ratio (95% CI)a,b
		Acute infection (IgM anti-HBc+) n=4	Chronic infection n=6
Median age (range) yrs	83 (59-93)	72 (59-73)	83 (72-85)	a: p=0.03 b: p=0.64
Male	6	0	0	a: OR 0 (0-1.5) b: OR 0 (0-2.6)
Diabetes	3	4	5	a: OR und (5.8-und) b: OR 38.3 (2.5-1886.3)
Blood glucose monitoring	2	3	4	a: OR 37.5 (1.6-2040.4) b: OR 25.2(1.8-385.7)
Insulin injections	2	1	3	a: OR 4.1 (0.5-99.7) b: OR 12.5(0.9 -186.1)
Podiatric care	20	3	5	a: OR 0.4 (0.02-5.9) b:  OR 1.75 (0.15-94.4)
HBV infected roommate	14	0	0	a: OR 0 (0-1.5) b: OR 0 (0-0.7)

a: For acute vs. susceptible 
b: For chronic vs. susceptible

Conclusions: This investigation identified a high prevalence of HBV infection among residents and staff at this facility. The exact mode of transmission was unclear, although the data suggests transmission could be associated with diabetes care. These findings illustrate the need for greater attention to HBV prevention efforts among residents and staff in long-term care settings.