Abstract
The role of anti-HBS antibody in reducing the probability of hepatitis after accidental exposure to serum from patients with hepatitis or carriers of HBS Ag was studied prospectively among 712 medical workers. One fourth of the workers were anti-HBS positive and less than one per cent of them developed hepatitis, in contrast to 11 per cent among those who were anti-HBS negative. Three coded immune-serum globulin preparations of varying anti-HBS titer were randomly assigned. Among 251 persons passively immunized with globulin having a conventionally low anti-HBS titer, hepatitis developed in 17 (seven per cent) within six months. Comparative rates among those receiving intermediately high titer and high titer globulin, respectively, were five per cent (11 of 208) and two per cent (5 of 253). The significantly lower incidence among the latter (P < 0.05) was offset by six additional cases, all in recipients of high titer globulin, detected when follow-up was extended to nine months. (N Engl J Med 293:1067–1070, 1975)