[Hepatitis B and C. Risk of transmission from infected health care workers to patients].

Hepatitis B and C viruses (HBV, HCV) cause chronic infections and high viremia which often remain undetected. Health care workers have an elevated risk of acquiring HBV or HCV when performing exposure-prone procedures and transmitting these viruses to patients. The extent of viremia varies considerably in different carriers and the risk of transmission is different for the various procedures. According to reports from the last 15 years, highly viremic HBV carriers with HBeAg transmit the virus on average to 4% of their patients when performing operations with high risk of injuries. HBeAg-negative surgeons with a viremia between 10(6) and 10(7) HBV DNA molecules/ml transmit to 1.5% of the patients. The absence of reports on proven transmission caused by viremia <10(5) molecules/ml suggests a residual risk below 1:100,000 that a surgeon with lower virus load transmits to one patient within 15 years. Eight cases were reported where HCV-infected surgeons transmitted the virus to 0.15% of their patients (17/11,119) and had (as far as tested) around 10(6) HCV RNA molecules/ml or more. Current recommendations of the relevant professional associations and institutions require vaccination of medical staff against HBV with control of immunity, regular examinations of staff for HCV, and in cases of missing immunity for HBV. Infected staff with viremia must either abstain from exposure-prone procedures or have a decision from an expert committee on the acceptability of such procedures in view of the individual infection status.