A Hepatitis B Outbreak Associated with Outpatient Chelation Therapy

BACKGROUND/OBJECTIVES: In 2004 a county health department identified two cases of acute hepatitis B among men (age ≥ 70 years) who denied traditional hepatitis risk factors. Interviews linked the men to the same clinical practice, where both had outpatient chelation therapy. In response the health department initiated an epidemiological investigation in February 2005. Objectives • To ascertain the existence of an outbreak • To determine the etiology of the outbreak • To implement preventive public health measures. METHODS: The health department conducted clinic visits to assess compliance with standard infection control practices and conducted a retrospective cohort study consisting of medical record reviews and patient interviews. Patients were screened for hepatitis through serologic survey. Samples from patients with acute (IgM positive) and chronic (HBsAg positive) hepatitis B infections were submitted to CDC for genotyping and nucleic acid sequencing. RESULTS: Violations of standard infection control practices included failure to prepare and store intravenous infusions under aseptic conditions, inconsistent hand hygiene, inconsistent use of personal protection (gloves), and inadequate cleaning of multidose vials prior to use. Of the estimated 253 clinic patients, 106 (42%) patients were tested for hepatitis. A total of 6 acute and 2 chronic hepatitis B cases were identified. The physician had chronic hepatitis and was also positive for the hepatitis B e antigen. All cases had received chelation therapy at the clinic (including the physician). Following the study, an additional chelation patient developed acute hepatitis B, resulting in a total of 9 hepatitis B cases. Five specimens were tested by CDC (including one from the physician), and all five were found to be of the same genotype and serotype which is consistent with a common source or transmission event. CONCLUSIONS: Both epidemiologic and laboratory data support hepatitis B transmission in this clinical practice. The high infectivity of the hepatitis B e antigen positive physician increased the consequences of breaks in infection control. This outbreak is one of the few documented instances linking transmission from a hepatitis B e antigen-positive health care professional to patients. Implementation of public health interventions, (including closing the practice) halted the hepatitis B transmission. More oversight of outpatient clinics may prevent future outbreaks.