The immune response of healthy adults to a reduced dose of hepatitis B vaccine

Three hundred thirty‐six medical personnel from hemodialysis centers were treated with three doses, 20 μg each, of the Merck hepatitis B vaccine (at 0, 1, and 6 months). Within 1 month after the first injection, 41% converted to anti‐HBs positivity; after the second injection the conversion rate rose to 80–90%; and after the booster, to 96–98%. The later rate remained unchanged during the 18‐month follow‐up period. Only 2.8% of those vaccinated did not respond to the vaccine. The patterns of immune responses to 20‐μg doses were found to be exactly the same as to 40‐μg doses. It is suggested that reduced doses of vaccine should be as efficacious as the larger ones.