The Japanese encephalitis vaccine became mandatory this past weekend for active-duty Airmen who are either permanently stationed or who will be temporarily assigned for more than 30 days to Japan or South Korea, according to a USAF press release.

Japan Image/CIA

“Even though the likelihood of getting Japanese encephalitis is low, the consequences of this disease can be real severe, including permanent disability or death,” said Lt. Col. Randy Langsten, the Pacific Air Forces Surgeon General command public health officer. “In this case, we’re talking about mitigating a specific medical threat. We’re placing an emphasis on keeping our force prepared to carry out the Air Force’s Pacific mission.”

The current vaccine has been available since 2009, and until now, has only been recommended for Airmen. Typically, the Air Force mandates any vaccine recommended by the Advisory Committee on Immunization Practices to the Centers for Disease Control and Prevention. To help bring this vaccine in line with standard practice, the Air Force made it mandatory.

The implementation was signed into effect Jan. 9, by Air Force Surgeon General Lt. Gen. Thomas Travis. The implementation also aligns with local country processes, which requires the vaccination for all host country children.

Members currently stationed in Japan and South Korea will see their individual medical readiness status turn yellow Feb. 1, and will have one year to receive the two-dose vaccination series.

Although not required, the Air Force recommends family members and Defense Department civilian employees in Japan and South Korea to receive the vaccine as well.

Japanese encephalitis (JE) is the most important cause of viral encephalitis in Asia.  A recent literature review estimates nearly 68,000 clinical cases of JE globally each year, with up to 20,400 deaths due to JE.

Most JE virus infections are mild (fever and headache) or without apparent symptoms, but approximately 1 in 250 infections results in severe disease. The case-fatality rate can be as high as 30% among those with disease symptoms.

JE is transmitted to humans through bites from infected mosquitoes of the Culex species (mainly Culex tritaeniorhynchus).