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日本腦炎疫苗 (減活疫苗)
Japanese encephalitis vaccine (Live attenuated vaccine)

日本腦炎是一種經蚊子傳播的疾病，主要由給帶有日本腦炎病毒的三帶喙庫蚊子叮咬而染病。蚊子於稻田等大量積水的地方繁殖，叮咬帶病毒的豬隻或野生雀鳥後就會受感染，再於叮咬人類或動物時將病毒傳播。

日本腦炎並無特定的治療方法，醫生一般對患者施以支援性治療。根據世界衛生組織的數據顯示，在感染者中，日本腦膜炎死亡率可高達 20-30%。曾患上日本腦炎的康復者中，約 30-50%的人有神經系統的後遺症。

而兒童更是高危人群，大約 75%的感染者是初生至 14 歲兒童。一些打算於日本腦炎流行的國家逗留一個月或以上的旅客應考慮接種日本腦炎疫苗。對於一些短期旅遊（不足一個月），旅客如果計劃於傳播季節在郊區逗留，並大部分時間進行戶外或夜間活動亦應考慮接種疫苗。

減活疫苗適合 9 個月或以上的人士接種。成人應在出發前最少 14 天接種疫苗，兒童則需要 28 天。

Japanese encephalitis is a mosquito-borne disease caused by the Japanese encephalitis virus. The virus is transmitted by the bite of infected mosquitoes. The principal type of mosquito that transmits the disease is called Culex tritaeniorhynchus. The infected mosquito transmits the virus to humans and
animals during biting. The mosquitoes breed where there is abundant water such as rice paddies and become infected by feeding on pigs and wild birds infected with the Japanese encephalitis virus. The disease is not directly transmitted from person to person.

There is no specific treatment for this disease. Supportive therapy is indicated. The case-fatality rate can be as high as 30% among those with symptoms. Of those who survive, 30% – 50% suffer permanent intellectual, behavioural or neurological problems such as paralysis, recurrent seizures or inability to speak.

Vaccination is recommended for travellers who plan to stay one month or longer in endemic areas, particularly in rural areas; and for short-term (less than one month) travellers if they plan to have significant extensive outdoor or night-time exposure in rural areas during the transmission season of
the disease.

Live attenuated vaccine approved for use in individuals from 9 months of age or above. The primaryimmunization schedule is one dose administered at least 14 days before travel in adults and at least 28
days before travel in children.