Abstract
During investigations to determine a satisfactory, practical preexposure regimen for administering rabies vaccine to groups of people at high risk, a total of 540 volunteers received vaccine of chick or duck embryo origin. The most practical regimen consists of two subcutaneous injections of 1.0 ml of duck embryo rabies vaccine given a month apart followed by a booster of 1.0 ml of the vaccine 7 months after the 2nd injection. Ninety percent of the volunteers who were on this regimen had a detectable serum neutralizing antibody titer one month after the last injection.