The hidden threats posed by Japanese encephalitis virus genotype V

Area of Science:

• Virology
• Epidemiology
• Immunology

Background:

• Japanese encephalitis virus (JEV) is a significant cause of viral encephalitis in Asia.
• Genotype V (GV) JEV has re-emerged as the predominant lineage in Korean mosquitoes, with associated human cases.
• Current JEV vaccines, based on genotype III (GIII), show limited efficacy against GV JEV.

Purpose of the Study:

• To review current evidence on GV JEV epidemiology, characteristics, and vaccine efficacy.
• To highlight the need for evaluating GV-specific vaccines due to insufficient protection from existing ones.
• To identify priorities for surveillance and future research on GV JEV.

Main Methods:

• Literature review of epidemiological data.
• Analysis of molecular and biological characteristics of GV JEV.
• Assessment of vaccine protection against GV JEV using existing studies.

Main Results:

• GV JEV exhibits distinct genomic, antigenic, and pathogenic properties compared to other genotypes.
• Animal studies suggest higher lethality associated with GV JEV.
• Breakthrough infections indicate partial and insufficient protection from current GIII-based vaccines against GV JEV.

Conclusions:

• The re-emergence of GV JEV poses a significant challenge to existing JEV control strategies.
• There is a critical need to assess the epidemiological and clinical impact of GV JEV.
• Development and evaluation of GV JEV-specific vaccines are warranted to address protection gaps.