Kurane I, Takasaki T
           Department of Virology 1, National Institute of Infectious Diseases,
           1-23-1 Toyama, Shinjuku-ku, 162-8640, Tokyo, Japan.
           Vaccine 2000 May 26;18 Suppl 2:33-5

        Mouse brain-derived, inactivated Japanese encephalitis (JE) vaccine has
        been internationally used for many years. It is believed that this
        vaccine made a great contribution to the reduction of JE patients in
        several countries. Mouse brain-derived, Beijing-1 and Nakayama JE
        vaccines induce high levels of neutralizing antibodies. High levels of
        induced antibodies are maintained at least for 3-4 yr. The induced
        antibodies are cross-reactive to heterologous strains; however, the
        neutralizing antibody titers against heterologous strains are usually
        lower than those against homologous strains. Considering that both
        Nakayama and Beijing-1 JE vaccines showed high levels of protective
        efficacy in Taiwan and Thailand where strains other than Nakayama and
        Beijing-1 were circulating, we conclude that the current inactivated JE
        vaccine can induce high levels of protective immunity against
        heterologous JE virus strains.