Immunogenicity of low dose Japanese encephalitis vaccine (BIKEN) administered by the intradermal route: preliminary data.

Two hundred twenty-four immune and non-immune adults were systematically assigned to receive a single dose of Nakayama strain JEVAC in one of four study "arms": 0.1 ml ID, 0.2 ml ID (injection of 0.1 ml at two sites), 0.3 ml ID (injection of 0.1 ml at three sites), or 1.0 ml SC. Immune responses after this single dose (in many cases "booster") was assumed to reflect immune responses of a primary series and was assessed qualitatively (percent seroconvertion) and quantitatively (geometric mean titer) a 30 and 90 days post immunization. The results showed that JEVAC given 0.1 ml. ID at two sites is likely to be as immunogenic as 1.0 ml. given SC.