Journal Reviews
Journal Reviews
Mizuno Y, Suzuki K, Mori M, et al. Study of needlestick accidents and hepatitis C virus infection in health care workers by molecular evolutionary analysis. J Hosp Infect 1997; 35:149-154.
Use of molecular epidemiology techniques may allow occupational transmission of hepatitis C virus to be documented even years after the fact if blood of the health care worker and source patient are available for testing, the authors report.
"Our experience shows that if serum can be collected from the source and the victim even two to three years after the accident, it is still possible to prove a causative relationship between HCV infection and a needlestick accident," the authors conclude.
The authors report that in a five-year period between 1989 and 1993, 87 needlestick accidents occurred among health care workers at their hospital. Thirty-seven (43%) of these needlestick accidents involved blood contaminated with hepatitis C virus, and two of them (5.4%) led to the occurrence of hepatitis C infection.
The first case involved a 43-year-old nurse who was accidentally injured by a needle contaminated with blood from a patient who had cirrhosis and hepatocellular carcinoma due to HCV. Acute hepatitis C infection occurred after five weeks and HCV RNA was positive after eight weeks. The second case was a 33-year-old nurse who was injured by a needle contaminated with blood from a patient who had chronic HCV. Liver function was normal at 11 days after the accident. However, HCV was diagnosed 21 months later after she had successfully given birth. The nucleotide sequence of HCV was determined in the two patients and the needlestick victims, and phylogenetic trees were constructed by molecular evolutionary analysis. On the basis of that work, transmission of HCV could be confirmed in both cases. The method of analysis may be useful for confirming the transmission of HCV even long after the event, the authors note.
"HCV-related needlestick accidents are major problems among health care workers, because there is no vaccine available and infection tends to become chronic," the authors conclude. "In addition, there is a high incidence of progression to cirrhosis and hepatocellular carcinoma after acute hepatitis C. . . . HCV appears to show a lower infectivity than HBV, but it is still necessary to confirm infection after an HCV-related needlestick accident, and to take appropriate countermeasures to prevent such infections."
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Shapiro C, Tokars J, Chamberland ME, et al. Use of the hepatitis-B vaccine and infection with hepatitis B and C among orthopaedic surgeons. Journal of Bone and Joint Surgery 1996; 78-A:1791-1800.
The prevalence of hepatitis C virus infection among orthopaedic surgeons agreeing to anonymous, voluntary testing at a medical conference was "several times greater than the prevalence in blood donors in the United States [and] suggests a possible occupational risk," authors from the Centers for Disease Control and Prevention report in this study. In addition, many older surgeons reported that they have not been immunized for hepatitis B virus, and 27% of those over 60 years old had evidence of infection.
The authors used a questionnaire with a guarantee of anonymity to the respondents, and performed serological testing for HBV and HCV on 3,411 attendees at the 1991 annual meeting of the American Academy of Orthopaedic Surgeons in Anaheim, CA.
Of 3262 participants who reported having no non-occupational risk factors and who were evaluated for infection with hepatitis C, 27 (less than 1%) tested positive for the antibody to HCV. However, the prevalence of infection with HCV increased with age, as none of 135 surgeons who were 20 to 29 years old had evidence of infection and five (1.4%) of 360 surgeons who were at least 60 years old had evidence of the virus.
"Controlled studies comparing health care workers with appropriate groups may help to determine the risk of HCV infection for health-care workers," they conclude. "In addition, cohort studies of large groups of health care workers may help to quantitate their risk of HCV infection more accurately; however, because of the over-all low rate of infection, such studies may be impractical."
There was evidence of infection with hepatitis B in 410 (13%) of 3,239 participants who had reported having no non-occupational risk factors. In addition, 2,103 (65%) reported that they had been immunized with the HBV vaccine. The prevalence of previous infection with HBV increased with increasing age, as 97 (27%) of 360 surgeons who were at least 60 years old had evidence of infection. Only four (3%) of 136 surgeons who were 20 to 29 years old were infected.
The prevalence of HBV vaccination decreased steadily with age. On the one hand, 123 (90%) of 136 surgeons who were in the 20-29 age range had been immunized. On the other, only 127 (35%) of 360 surgeons age 60 years and older had received the vaccine.
The prevalence of infection with HBV or HCV was not associated with the reported exposures to blood of patients, such as number of percutaneous injuries reported by respondents over the previous year. For the participants who reported having no non-occupational risk factors, prevalence of infection with hepatitis C was significantly associated with the age, the occupational status, and the number of years of practice.
While encouraged by the large percentage of younger participants in the study who reported that they had been immunized for HBV, the authors noted that of the 3,239 participants who reported having no non-occupational risk factors, 727 (22%) had not received the vaccine and were susceptible to infection.
"The lower prevalence of immunization for the older orthopaedic surgeons indicates that more efforts are needed to encourage vaccination for this group," they concluded.
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