Two distinct types of non‐A, non‐B hepatitis in a cardiovascular surgical unit

The incidence of non‐A, non‐B hepatitis in a cardiovascular surgical unit was examined among the 204 patients who received blood transfusion and extracorporeal circulation while undergoing open heart surgery during April 1979 to December 1981. Among 115 adult patients (20 to 69 years old) 46 (43%) developed non‐A, non‐B hepatitis, whereas the incidence in younger patients (1 to 19 years old) was much lower (21.8%, 19 out of 89). When monthly incidence was examined during the study period, two nosocomial epidemics, the first during September 1979 to February 1980 and second during October 1980 to January 1981, were found. When clinical features such as maximum ALT level and the proportion of icterus were examined, the features of the above two epidemics were taken to be different from those consistently observed through the study period. The epidemic type hepatitis not only resulted in more severe clinical features than the nonepidemic type, but the sera of the former contained immune complexes at a higher rate (80%) than did the latter (7.6%).