What is varicella zoster immune globulin?

Varicella zoster immune globulin (VariZIG, Saol Therapeutics) is a human blood product prepared from plasma obtained from healthy, volunteer blood donors identified by routine screening to have high antibody titers to varicella-zoster virus. The first varicella zoster immune globulin, VZIG, became available in 1978. In a study of immunocompromised children who were administered VZIG within 96 hours of exposure, approximately one in five exposed children developed clinical varicella, and one in 20 developed subclinical disease compared with 65%—85% attack rates among historical controls. In 2006, VZIG was discontinued and a new product, VariZIG, became available.