Tick-borne encephalitis in China: A review of epidemiology and vaccines.

Tick-borne encephalitis (TBE) has been shown to be endemic in northern and western China, including the three mountain areas in Heilongjiang, Jilin, Inner Mongolia, and Xinjiang. In addition, serology evidence shows that there is human infection in south-west provinces of China, including Xizang (Tibet) and Yunnan. TBE in China is caused by the Far Eastern TBE virus subtype and there is no biphasic course for disease presentation. The majority of TBE cases in China have occurred in people who were living or working in forests. TBE vaccines became available in China soon after the virus was identified in the country and they have been used for more than 60years to date, with different vaccine types used in different periods. Currently, an inactivated and purified whole-virus vaccine produced in a primary hamster kidney (PHK) cell line is used. Clinical trials have shown this vaccine to have higher immunogenicity and fewer adverse reactions than previous TBE vaccines. This paper provides a review on the epidemiology of TBE and the history of TBE vaccination in China.