Japanese encephalitis, live attenuated

Japanese encephalitis is a disease caused by the mosquito-borne Japanese encephalitis virus (JEV). Japanese encephalitis vaccine acts by inducing antibodies that neutralize live JEV. Accumulated data from animal studies, clinical trials of other JE vaccines, and human epidemiological studies, suggest that a virus neutralizing antibody response, as measured in vitro in a 50% plaque-reduction neutralization antibody test (PRNT₅₀) with a threshold titer of ≥1:10, provides evidence of protective immunity^10,11. The evaluation of vaccine effectiveness of Japanese encephalitis vaccine was therefore based on neutralizing antibody response using a threshold PRNT₅₀ titer of ≥1:10.