Immunogenicity of low-dose intramuscular and intradermal vaccination with recombinant hepatitis B vaccine

Abstract

The study is a randomized trial using recombinant DNA vaccine to determine whether an intramuscular 10 μg dose or intradermal 2 μg induces satisfactory anti-HBs levels compared to the standard dose of intramuscular 20 μg. Participants were 359 healthy medical and nurse students randomly allocated to one of the three groups: Group I - IM 20 μg; Group II - IM 10 μg; Group III - ID 2 μg at 0, 1 and 6 months. Anti-HBs titres were measured after complete vaccine schedule by ELISA/Pasteur. Baseline variables were similar among groups and side effects were mild after any dose. Vaccinees in the IM-10 μg group had seroconversion rate and geometric mean titre (GMT 2344 IU L-1), not significant different from the IM-20 μg group (GMT 4570 IU L-1). On the contrary, 21.4% of the ID - 2 μg recipients mount antibody concentration below 10 IU L-1 and GMT of 91 IU L-1, a statistically significant difference compared with the standard schedule IM-20 μg (p < 0.001). A three dose regimen of half dose IM could be considered an appropriate schedule to prevent hepatitis B in young health adults which is of relevance to the expansion of hepatitis B vaccine programme.