NEWS
12/18/1992

<TITLE>The licensing of a vaccine against Japanese encephalitis</TITLE>
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P92-40                                          Food and Drug Administration
FOR IMMEDIATE RELEASE                           Monica Revelle (301) 443-4177

    The Food and Drug Administration today announced the licensing of a       
vaccine against Japanese encephalitis.  The Japanese encephalitis virus,      
which is mosquito-borne, is common in parts of Japan, other Pacific Islands   
and the Far East, and it can cause a fatal inflamation of the brain.
    Infection with the virus leads to overt disease in only one of 200        
instances.  Illness, however, is usually severe, resulting in death in 25     
percent of cases and residual brain disorders in an additional 50 percent of  
cases.
    The new vaccine is recommended for certain travelers to Asia -- persons   
spending a month or more in areas where the virus is prevalent, or those on   
a trip involving extensive outdoor activities in rural areas.  The labeling   
will advise travelers also to take personal precautions to reduce exposure    
to mosquito bites.
    "This new vaccine represents a major improvement," said FDA Commissioner  
David A. Kessler, M.D.  "It is safer and more effective than previously       
available products."
    To determine efficacy, the U.S. Army conducted a controlled trial,        
involving 65,224 Thai children, that demonstrated a 91 percent efficacy rate  
for the vaccine.
    In 1990, the U.S. Army conducted a safety and immunogenicity clinical     
trial of the vaccine at two different dosing schedules.  At two months, all 
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                                                 Page 2, P92-40, Encephalitis
of those vaccinated had developed antibodies.  One year later, all of the     
252 patients vaccinated who volunteered to be sampled still had the           
protective antibodies.
    In June 1992, FDA's Vaccines and Related Biological Products Advisory     
Committee, a panel of outside experts, recommended approval of the new        
vaccine.  The panel had previously received data concerning allergic          
reactions that had been reported in non-U.S. populations.
    This recommendation was based on additional clinical data from a study    
conducted by the U.S. Navy regarding allergic adverse reactions following     
immunization with the vaccine.  In this study, the U.S. Navy immunized        
35,253 active duty military personnel and their dependents following an       
outbreak of Japanese encephalitis on Okinawa.  The overall adverse reaction   
rate was 62 per 10,000 persons vaccinated, and reactions were generally mild  
to moderate, including hives, itching and wheezing.  Nine persons were        
hospitalized (3 per 10,000 persons vaccinated), primarily to allow for        
administration of intravenous steroids for hives.  None of these reactions    
were considered life-threatening.
    Approximately 20 percent of those who received the Japanese encephalitis  
virus vaccine experienced mild to moderate local side effects including       
tenderness, redness and swelling.  Ten percent reported fever, headache,      
malaise, rash, chills, dizziness, muscle pain, nausea, vomiting or abdominal  
pain.
    Persons with certain allergic histories appear to be more likely to       
experience an adverse reaction following vaccination.
    The Japanese encephalitis virus vaccine is manufactured by the Research   
Foundation for Microbial Disease of Osaka University, Japan (BIKEN).          
Connaught Laboratories, Inc., Swiftwater, Penn., is the U.S. distributor.
    FDA is a Public Health Service agency within HHS.
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