High seroprotection rate induced by intradermal administration of a recombinant hepatitis B vaccine in young healthy adults: comparison with standard intramuscular vaccination.

Intradermal (ID) vaccination has been proposed as a cost-saving alternative for administration of Hepatitis B (HB) vaccine to implement of mass vaccination of high-risk groups, particularly in developing countries. Therefore, the effectiveness of ID vaccination needs to be evaluated and verified in different ethnic backgrounds. The present study is a randomized trail using a recombinant vaccine (Heberbiovac) to compare immunogenecity and safety of an intradermal low-dose (4 microg) with standard dose (20 microg) of intramuscular (IM) vaccination in healthy Iranian population. Participants were 143 healthy Iranian medical and nursing students randomly allocated to ID or IM vaccination group. The vaccine was inoculated at 0, 1 and 6 months intervals. Serum samples were collected 1 month after the last vaccination and the anti-HBs response was determined using ELISA. The overall seroprotection rate (anti-HBs level > or = 10 IU/L) was 97.3% for ID vaccination group, which was not different from that of IM vaccination group (98.55%) (p = 0.99). Similarly, geometric mean titers (GMT) of anti-HBs were not significantly different between ID (1164.1 IU/L) and IM (1071.8 IU/L) vaccination groups (p = 0.4). There was no significant difference in seroprotection rate and GMT of anti-HBs between sexes. Although induration and hyperpigmentation at the site of injection were more frequently observed in ID vaccination group, no other clinically adverse effects were observed in both vaccination groups. We conclude that the ID route, which would require one-fifth of the standard dose, would be suitable for use in certain groups such as high-risk adults when the cost of vaccine is the inhibiting factor for mass vaccination.