[Collection of anti-HBs hyperimmune plasma: stimulation by Genhevac B in weakly immunized donors]

The need for anti HBs globulin is still important in spite of the development of the HBs vaccination. Twenty-two plasma donors, immunized against Hepatitis B virus (HBV) with titers of anti HBs between 100 and 6,000 milli International Units per ml (mUI/ml), received two injections of Genhevac B Pasteur at a one-month interval, and a third injection two months later whenever the answer was still under 6,000 mUI/ml, which is the minimum necessary in order to obtain a specific globulin compatible with the National Standard (100 UI/ml) from plasma fractions. In this programme, no severe adverse reaction was documented, and the mean rate of anti HBs rose from 1,322 to 35,173 mUI/ml, with a mean multiplying factor of 20.2. This result was reached after the first injection in "responders"; the third injection did not increase the titer in "non responders". The titer was still above 6,000 mUI/ml after six months in all the donors with more than 1,500 mUI/ml before vaccination. This limit is suggested to select plasma donors for vaccination, and a booster injection could be proposed every six months.