A Review of Japanese Encephalitis Vaccines with Respect to Potential Veterinary Use.

Abstract

Background: Japanese encephalitis virus (JEV) is a reemerging vector-borne orthoflavivirus of significant public and animal health concern. Infection with JEV can cause inapparent, mild, or fatal encephalitis in humans and animals. The virus, which circulates primarily in Southeast Asia, has caused outbreaks in humans and livestock in nonendemic regions, leading to human disease and significant economic loss. The 2022 Australian outbreak of JEV led to renewed interest in JEV countermeasures available in the United States for veterinary use as the Australia outbreak primarily affected commercial swine farms. There are currently no antivirals or veterinary vaccines available to protect animals from JEV infection, and only one vaccine is approved for human use in the United States. In the event of a JEV introduction to the United States, vaccination of susceptible reservoirs, like domestic swine, may help prevent economic loss and JEV from establishing endemicity in the United States.

Methods: This review assesses recent advances in JEV vaccine development with an interest in veterinary applications. This systematic review was conducted by searching databases (PubMed, Web of Science, Scopus, and EBSCOhost).

Results: Eighty-seven research articles focused on the evaluation of novel JEV vaccine candidates were included in this review.

Conclusion: Although there are a variety of different methodologies being employed in the development of JEV vaccine candidates, including recombinant live virus vaccines utilizing insect-only flaviviruses as vectors for JEV antigens and virus-like particle vaccines using various JEV genes to elicit protection among different JEV genotypes. While there are many promising candidates being developed, most are likely several years away from commercial production and would not be available if JEV were introduced to the United States within the next several years. Therefore, other disease control strategies should be investigated.