[Comparative efficacy of intradermal and intramuscular active immunization against hepatitis B with a recombinant...

Preliminary results of a prospective, comparative and randomized study on 119 sero-negative volunteers with increased risk to acquire hepatitis B, aimed to evaluate the comparative efficacy of a recombinant vaccine administered either intramuscularly or intradermally, are discussed. A short vaccination schedule of three consecutive doses given on months 0, 1 and 2 was used. Distribution by sex and age for both groups was similar. Seroconversion and seroprotection rates were comparable (96% and 96% Vs. 98% and 93%, respectively). The geometric mean titre of anti-HBsAg in individuals immunized via I.M. (155 IU/L) was significantly higher to that of the I.D. group (71 IU/L). On the other hand, the rate of good response (> 100 IU/L) was also higher in the I.M. group (67% Vs. 39%). The percentage of good responder in women was consistently higher than in men for both groups (75% Vs. 13%, respectively). In 68 vaccinees, samples were obtained one year later. The levels of anti-HBsAg and the anamnesic response after a booster of the vaccine are currently being assayed.