Immunogenicity of low dose hepatitis B vaccine by the intradermal route & persistence of anti-HBs after three years.

ABSTRACT

Plasma derived hepatitis B vaccine given intradermally (0.2 ml; 4 micrograms HBsAg) at 0, 1, 6 months to 200 health care workers, produced seroconversion in 97.5 per cent. Antibody levels to hepatitis B surface antigen (anti-HBs) crossed 1000 mIU/ml in 62 per cent while 26.5 per cent had levels of 100 to 1000 mIU/ml. Anti-HBs levels persisted in the same range in 41.7 per cent but dropped by a log in 58.3 per cent subjects at the end of 3 yr. Protective antibodies above 10 mIU/ml were documented in 93.3 per cent vaccinees after 3 yr. The 0.2 ml vaccine by intradermal (id) route was also found to give a good booster effect in another group of 27 persons who had received full dose vaccine 5 yr earlier. Thus, 0.2 ml vaccine by id route was safe, gave high seroconversion and persistent antibody levels over 3 yr and could offer effective protection at an economic cost.