Immunology Hepatitis B And C

Immunology

Hepatitis B and C virus transmission during surgical interventions has become a critical concern. Healthcare workers are especially prone to catch HBV and HBC infections from patients and vice versa. Statistics derived from several studies over the last decade and a half reveal a 4% infection rate for patients of surgeons who are positive for HbeAg. [1] This study under consideration by Harpaz et.al (1996) analyzes this important clinical issue of transmission of the HBV from a previously infected surgeon to his patients. The Physician under study tested positive for the hepatitis B surface antigen (HBsAg) and anti-HBc (antibody) and was diagnosed with jaundice in February 1992. However, by March 1992 when he symptomatically recovered, he resumed his duties as a surgeon in two hospitals. This retrospective cohort study analyzed the period between July 1991 and July 1992 and reviewed a total of 144 patients who received surgical care from the particular doctor. [2]

The researchers used chart reviews, interviews and serologic testing for patients who received surgical care from the physician under study in two hospitals where he was working during the aforementioned study period. A total of 19 patients out of 144 (13%) study subjects (those who were operated by the surgeon) developed HBV infection post surgery. As a control group, the researchers also observed 124 patients who received surgical care from other thoracic surgeons in one of the hospitals under study. This was useful in identifying any other hospital-based potential infection sources. However, the fact that none of these 124 subjects were positive for HBV post surgery clearly ruled out infection by other nosocomial sources. Serological testing further revealed that the HBsAg subtype adW2 found in the surgeon was common in 13 infected subjects. Further HBV DNA sequence from the surgeon matched that of 9 case subjects who were also tested. Thus the study rightly identified the doctor under study to be the source of infection. [2]

The researchers reported to have identified traces of HBV DNA and HBsAg from the lesions that were formed during the one-hour suture simulation test. This retrospective study concluded that the lesions formed during suturing in combination with glove failure could have been the possible route of transmission of the HBV. However, the study failed to point out any conclusive evidence as to the route of transmission. It was revealed from the study results that cardiac transplantation procedure (relative risk, 4.9; 95% confidence interval, 1.5 to 15.5) carried greater risk factor for HBV infections.

The one big drawback of this study is the vagueness of the results. Though the source of infection is clearly established, the researchers were not able to pinpoint the exact route of transmission. Furthermore, it is clear from the information that was directly gathered from the surgeon that he had clearly violated atleast one of the standard of surgical procedures. The surgeon had admitted to applying hemostatic material to sternal incisions without the use of sponges, which is not recommended due to the possibility of glove tears and percutaneous contact. Therefore, there is atleast some evidence for 'inadequate infection control'. However, it must be added that the rare percutaneous exposure does not account for the high rate of infection as identified in this study.