On Jul. 19, 2019, the Centers for Disease Control and Prevention (CDC) published recommendations from the Advisory Committee on Immunization Practices (ACIP) regarding prevention of Japanese encephalitis (JE) among U.S. travelers and laboratory workers.

JE virus, a mosquitoborne flavivirus, is the most common vaccine-preventable cause of encephalitis in Asia. JE occurs throughout most of Asia and parts of the western Pacific. Approximately 20%–30% of patients die, and 30%–50% of survivors have neurologic, cognitive, or behavioral sequelae. No antiviral treatment is available.

Inactivated Vero cell culture–derived JE vaccine (Ixiaro [JE-VC]) is the only JE vaccine that is licensed and available in the United States. In 2009, the U.S. Food and Drug Administration (FDA) licensed JE-VC for use in persons aged ≥17 years; in 2013, licensure was extended to include children aged ≥2 months.