Transfusion-transmitted HBV infection with isolated anti-HBs-positive blood.

Whatever the basic infection state, blood donors with isolated weak anti-HBs may include a small population with a risk of causing TT-HBV. Identifying individuals harboring such TT-HBV risk among individuals positive only for anti-HBs is difficult under current screening strategies. Active surveillance for the occurrence of TT-HBV with blood positive only for anti-HBs is necessary.