Factors influencing postexposure immunoprophylaxis of hepatitis B virus infection with hepatitis B immune globulin. High deoxyribonucleic acid polymerase activity in the inocula of unsuccessful cases.

Hepatitis B immune globulin was given intramuscularly to 102 staff members of a dialysis unit within 48 h after the accidental needlestick exposure to blood containing hepatitis B surface antigen (HBsAg). Hepatitis B virus (HBV) infection developed in 11 of 56 persons (20%) who had been exposed to blood containing hepatitis B e antigen (HBeAg). Among 56 HBeAg-positive inocula, HBsAg-associated deoxyribonucleic acid polymerase activity in the 11 inocula that transmitted HBV infection was significantly higher than that in the remaining 45 inocula that did not (log counts per minute 3.27 +/- 0.57 vs. 2.09 +/- 1.19, p less than 0.001). These 11 HBeAg-positive inocula revealed higher hemagglutination titers of HBsAg (geometric mean 13.5 +/- 1.4 vs. 11.2 +/- 3.2, p less than 0.001). The receptor for polymerized human serum albumin was detected significantly more often in the inocula that transmitted HBV infection than those that did not (10/11 vs. 24/45, p less than 0.05). Based on the results obtained, the failure in protecting all of those exposed to HBeAg-positive blood would be attributable to a high concentration of HBV in some HBeAg-positive inocula and the inability of intramuscular injection to raise a protective level of antibody in the circulation immediately.