Objectives: To establish the etiology for outbreaks of hepatitis B virus (HBV) infections at two assisted living facilities (ALFs) and devise appropriate control measures.
Design: Multisite outbreak investigations, retrospective cohort.
Setting: Two ALFs in Illinois.
Participants: Facility A residents (n=120) and Facility B residents (n=105) and nursing staff (n=6).
Measurements: For Facility A, a retrospective cohort study to identify risk factors for HBV infection through serological testing of all residents and a medical record extraction. For Facility A and B, investigation of fingerstick blood glucose monitoring techniques. For Facility B, serological HBV testing of nurses and residents receiving fingerstick blood glucose monitoring.
Results: At Facility A, five confirmed acute, two probable acute, and one probable chronic HBV infections were identified in the 109 residents tested. All of the eight identified residents with HBV infection had diabetes mellitus. HBV deoxyribonucleic acid (DNA) sequences from the chronic and acute cases were identical. Transmission of HBV was associated with fingerstick blood glucose monitoring (relative risk (RR)=28.5, 95% confidence interval (CI)=1.6-498; P<.001) and insulin injections (RR=7.4, 95% CI=1.3-40.8; P=.03). At Facility B, seven of 21 residents (33.3%) receiving fingerstick blood glucose monitoring had evidence of recent HBV infection.
Conclusion: Nurses probably transmitted HBV infection from resident to resident during fingerstick blood glucose monitoring in two separate ALFs, causing outbreaks. Awareness of the high risk for HBV transmission during procedures for the care of diabetes mellitus was limited. Following established infection control measures is critical to prevent spread of this highly contagious virus.