Transmission of Hepatitis B Associated with Hemodialysis: Role of Malfunction (Blood Leaks) in Dialysis Machines

Abstract

In the first 10 months of 1974, 26 of 60 susceptible patients in a commercial hemodialysis unit developed asymptomatic infection with hepatitis B virus; 17 (65%) of the 26 cases occurred in 14 weeks from July to October. In a case-control study, 15 of 16 cases for whom records were available were found to be associated with malfunctions of dialysis machines (primarily leaks or ruptures in dialysis membranes) that had occurred before patients converted to hepatitis B surface antigen (HB_s Ag) positivity. In comparison, 17 of 34 controls were associated with machine malfunctions (P > 0.01). In addition, the mean number of malfunctions in machines per patient was significantly greater for cases of infection (2.25 ± 1.34) than for controls (1.06 ± 1.39) (P > 0.01). Furthermore, a direct correlation was demonstrated between an increase in blood leaks in machines used with susceptible patients and subsequent increases in cases of hepatitis for the various beds in the unit (r = 0.994, P > 0.0001). The mean period from the last blood leak to HB_s Ag seroconversion was 67 days. Six of the 36 blood leaks associated with cases of infection occurred 0.05). These data suggest that the conversion to HB_s Ag positivity was linked to the occurrence of machine malfunctions (blood leaks) and that events which occurred during these episodes caused the spread of infection.