A Publication for the Prevention of Occupational Transmission of Bloodborne Pathogens

Introduction SIMULTANEOUS CO-INFECTION WITH HUMAN immunodeficiency virus (HIV) and hepatitis C virus (HCV) following an occupational exposure in healthcare settings is, fortunately, a rare event. Since the first documented case of occupational HIV transmission was reported 20 years ago1, ten cases of co-infection in healthcare workers (HCWs) have been reported worldwide in the medical literature. While there are too few cases to make general recommendations for management, an analysis of the cases does yield some useful observations. Risk assessment: When assessing the serostatus of source patients, it is important to remember that spontaneous disappearance of antibodies to HCV has been reported2, and that HCV “sero-reversion” is 2-1/2 times more likely in HIV-positive than in HIV-negative patients.2-4 Furthermore, HCV RNA has been detected in HCV-antibody-negative patients, especially those who are immunocompromised, at a prevalence rate of about 3%.5 A case has been reported in the U.S. of a nurse who sustained a needlestick from a source patient who had end-stage AIDS but tested negative for HCV at the time of the exposure. However, the nurse seroconverted to both HIV (at 9-1/2 months postexposure) and HCV (at one year postexposure). The patient died shortly after the exposure and could not be retested, but an investigation of the case led to the conclusion that the nurse’s HCV infection was most likely due to her occupational exposure, since she had no other risk factors for HCV.6 In Italy’s national surveillance program that tracks HCWs’ exposures to bloodborne pathogens (SIROH), two similar cases, involving HCV only, were observed—i.e., the HCW was infected with HCV after an occupational exposure, although the source patient tested negative for the virus at the time of exposure (Gabriella De Carli, SIROH, personal communication). Such cases reinforce the importance of storing a plasma sample from both the source patient and the HCW following an occupational exposure, particularly when underlying conditions, such as severe immunodepression, may alter the validity of a screening test performed at the time of the exposure. Diagnosis: Two cases of co-infection (including the one mentioned above) had an unusually long incubation period for both HIV and HCV; clinical symptoms did not appear until more than six months after exposure, and seroconversion was delayed until more than nine months postexposure.6,7 There is evidence of a pathogenic interaction between the two viruses, but it has not been fully characterized. Guidelines from the Centers for Disease Control and Prevention †Department of Epidemiology, National Institute for Infectious Diseases, Lazzaro Spallanzani Hospital, Rome, Italy ‡International Healthcare Worker Safety Center, U.Va. Health System, Charlottesville, Virginia Reported Cases Worldwide in the Medical Literature and News Reports