Outbreak of hemodialysis-associated non-A, non-B hepatitis and correlation with antibody to hepatitis C virus.

Between January 1987 and October 1988, 35 (45%) of 77 patients undergoing chronic hemodialysis at one unit developed serum alanine aminotransferase (ALT) elevations suggestive of non-A, non-B hepatitis (NANBH). Patients were grouped by level of ALT elevation and presence of other etiologies for liver injury. All dialysis patients and staff were tested for antibody to hepatitis C virus (anti-HCV) by enzyme immunoassay on three occasions, 9 months apart; anti-HCV repeatedly reactive specimens were tested by the HCV neutralization assay. Household and sexual contacts of patients were tested once for anti-HCV. Case-patients were classified on the basis of clinical case definitions as probable, possible, questionable, and noncases, and by anti-HCV testing. Case-patients who had no history of transfusions or parenteral drug use were compared with noncases for common exposures. A total of 35% (27/77) of patients and none (0/24) of staff were anti-HCV-positive. Anti-HCV was found in 82% of probable cases, compared with 44% of possible cases, 44% of questionable cases, and 12% of noncases (P less than 0.01). Neither a common source nor direct person-to-person transmission could be documented; however, inadequate infection control measures demonstrated by lack of glove use and poor handwashing occurred during the exposure period. The incidence of HCV infection in patients over an 18-month period was 5%. Transmission of HCV to household or sexual contacts of patients did not appear to occur.(ABSTRACT TRUNCATED AT 250 WORDS)