WHO working group on the quality, safety and efficacy of Japanese encephalitis vaccines (live attenuated) for human use, Bangkok, Thailand, 21–23 February 2012

• Update of live-attenuated JE vaccine development.
• Update of licensing and use of live-attenuated JE vaccines.
• Update of regulatory review and considerations in environmental risk assessment and safety for live recombinant JE vaccine.
• Key issues and conclusions of the 2012 Bangkok meeting of WHO working group on live-attenuated JE vaccines.

Japanese encephalitis (JE) is one of the most important viral encephalitides in Asia. Two live-attenuated vaccines have been developed and licensed for use in countries in the region. Given the advancement of immunization of humans with increasing use of live-attenuated vaccines to prevent JE, there is increased interest to define quality standards for their manufacture, testing, nonclinical studies, and clinical studies to assess their efficacy and safety in humans. To this end, WHO convened a meeting with a group of international experts in February 2012 to develop guidelines for evaluating the quality, safety and efficacy of live-attenuated JE virus vaccines for prevention of human disease. This report summarizes collective views of the participants on scientific and technical issues that need to be considered in the guidelines.