目的  以Vero细胞为基质，研制安全有效的乙型脑炎灭活疫苗。方法  将经Vero细胞适应的乙型脑炎病毒P3株接种Vero细胞，培养后收获病毒液。采用β-丙内酯灭活，通过超滤浓缩、硫酸鱼精蛋白沉淀、蔗糖密度梯度离心等方法纯化病毒，最终配制成预防乙型脑炎病毒感染的疫苗。通过临床试验考察疫苗的安全性及免疫原性。结果  该疫苗的主要考核指标，如病毒滴度、总蛋白含量、Vero细胞DNA残留量、效价等均符合国家标准。临床观察结果显示，接种本疫苗后局部及全身反应轻微；各年龄组乙型脑炎病毒中和抗体阳转率均＞90%。结论  采用本法制备的疫苗安全有效。

Objective  To develop a safe and efficacious inactivated JE vaccine base on Vero cells.   Methods   A JE virus P3 strain adapted on Vero cells was inoculated and cultivated on Vero cells. The virus harvest was inactivated with β-propiolactone. Then the inactivated virus was concentrated by ultra-filtration, precipitated with protamine sulfate and purified by sucrose density gradient centrifugation. Finally the purified virus was formulated to be the vaccine. The vaccine was studied for safety and immunogenicity through clinical trials. Results   The virus titer, total protein contents, residual DNA contents and potency of the vaccine met the requirements of the Chinese Pharmacopoeia (edition 2005). The clinical trials showed that local and systemic reactions were minimal and antibody positive conversion rates in all age groups tested reached above 90% after vaccination. Conclusion   The inactivated JE vaccine prepared by this process is safe and effective.