Applying CDC guidelines to HBV, HCV transmission
February 1, 1997 4 minutes read
Applying CDC guidelines to HBV, HCV transmission
Harpaz R, et al. Transmission of hepatitis B virus to multiple patients from a surgeon without evidence of inadequate infection control. Engl J Med 1996; 334:549-554. Estaban JI, et al. Transmission of hepatitis C virus by a cardiac surgeon. N Engl J Med 1996; 334:555-560.
Two strikingly parallel articles address transmission of hepatitis from cardiac surgeons to patients. Harpaz and colleagues describe an investigation of a patient who suffered acute hepatitis B following a thymectomy. A thoracic surgery resident who had recently had acute hepatitis B assisted in the procedure. Subsequent investigation found that 19 of 144 hepatitis B-susceptible patients in whose surgery he participated had become infected, for an attack rate of 13%. Transmission occurred during a variety of procedures; the transmission rate was highest during cardiac transplantation (50%).
Comparison of HBV DNA sequences of specimens taken from the surgeon and nine patients showed identical sequences, shared by none of 19 samples from patients with community-acquired hepatitis B infection. The investigators were not able to identify any deficiencies in the surgeon’s technique or in compliance with infection control policies. However, the surgeon was hepatitis B e-antigen (HBeAg) -positive; the HBV DNA concentration in his serum was quite high (15 ng/mL).
While performing a study of the efficacy of second-generation assays for hepatitis C virus in the prevention of transfusion-related hepatitis, Estaban and colleagues found two patients who had contracted hepatitis C after cardiac surgery, despite having received only seronegative blood. Further investigation found a total of six patients who had surgery performed by a single cardiac surgeon known to have chronic hepatitis C infection. Genotyping and phylogenetic tree analysis of HCV RNA showed that five of the six patients appeared to have acquired infection from the surgeon. The infection rate among his patients was 2.9%. The quantity of HCV RNA in the surgeons serum was quite high (22 x 106 genome equivalents/mL).
The investigators were unable to identify any deficiencies in the surgeon’s technique. However, he reported an average of 20 percutaneous injuries per 100 procedures, with most occurring while tying wires during closure of the sternum. Other cardiac surgeons confirmed that percutaneous injuries were common during sternal closure.
Comment by Robert R. Muder, MD, hospital epidemiologist, Pittsburgh VA Medical Center.
Current recommendations from the Centers for Disease Control and Prevention for prevention of transmission of HBV and HIV from health care workers to patients define "exposure prone procedures" as those that "include digital palpation of a needle tip in a body cavity or the simultaneous presence of [the health care worker’s] fingers and a needle or other sharp instrument or object in a poorly visualized or highly confined anatomic site."1 The guidelines go on to recommend that "[health care workers] who are infected with HIV or HBV (and are HBeAg-positive) should not perform exposure-prone procedures unless they have sought counsel from an expert review panel about the advisability of continuing to perform these procedures."
Most thoracic surgical procedures would not qualify as exposure-prone under this definition. Visualization of the operative field is typically quite good. However, the use of sharp wires to close the sternum, which itself may have jagged edges, appears to be associated with a high frequency of percutaneous injury on the part of the surgeon.
It is interesting to note that the rate of transmission of hepatitis C from surgeon to patient in the second report, 2.9%, is similar to that reported from HCV-infected patient to health care worker after a needlestick (2% to 3%), suggesting that such injury may be even more common than the surgeon appreciated. The hepatitis B-infected surgeon, however, transmitted infection during a variety of procedures, including at least one that did not include sternotomy. The high rate of transmission occurring among his patients may be explained in part by the fact that he was HBeAg-positive, and had a very high plasma viral load. Finally, as Harpaz et al point out, the epidemic of hepatitis B could have been prevented had the surgeon received hepatitis B vaccine.
Although it’s always risky to make broad generalizations from single case reports, I believe it is reasonable to expand the definition of exposure-prone procedures to include those requiring sternotomy. In addition, it appears that HBeAg-positive surgeons can transmit infection during other procedures that are not exposure-prone, even if standard blood and body substance precautions are followed.
Even more uncertainties exist regarding the risk of transmission of hepatitis C from surgeons to patients during invasive procedures, in large part because detection of HCV infection has only become possible rather recently. Until more epidemiological studies are available, it appears reasonable to apply CDC recommendations for exposure-prone invasive procedures to health care workers infected with HCV as well.
Reference
1. Centers for Disease Control and Prevention. Recommendations for preventing transmission of human immunodeficiency virus and hepatitis B virus to patients during exposure-prone invasive procedures. MMWR 1991; 40:1-9.
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