Outcomes of a patient‐to‐patient outbreak of genotype 3a hepatitis C

Between March 2000 and July 2001, at least 99 persons acquired a hepatitis C virus genotype 3a (HCV‐3a) infection in an oncology clinic. This nosocomial HCV outbreak provided an opportunity to examine the subsequent clinical course in a well‐defined cohort. This was a retrospective/prospective observational study of the short‐term significant health outcomes of a large, single‐source, patient‐to‐patient HCV‐3a outbreak. Outbreak patients or their legal representatives consenting to study were enrolled between September 2002 and December 2007. We measured history and physical examinations, medical records, HCV serology, HCV RNA and genotype, liver enzymes, histology, response to antiviral therapy, and liver‐related morbidity and mortality. Sixty‐four of the 99 known HCV‐3a outbreak patients participated. During a 6‐year period, six patients developed life‐threatening complications from liver disease, three died, one received a liver transplant, and two were stable after esophageal variceal banding or diuretic therapy of ascites. Thirty‐three patients underwent antiviral therapy, with 28 achieving a sustained viral remission. One patient acquired HCV‐3a infection sexually from an outbreak patient and was successfully treated. Eleven study patients died of malignancy, including two that had achieved a sustained viral remission after antiviral therapy. Conclusion: Our patient cohort had a nosocomial source and an oncologic or hematologic comorbidity. Compared with previous HCV outcome studies, a patient‐to‐patient HCV outbreak in an oncology clinic exhibited significant morbidity and mortality. Attention is needed to the public health risk of nosocomial HCV transmission, emphasizing infection control, early diagnosis, and therapy. (HEPATOLOGY 2009.)