目的  比较乙型脑炎减毒活疫苗病毒滴度单瓶平行检测与多瓶混样检测之间的差异性，为进一步完善中国药典中相关技术要求奠定基础。方法  1人份和5人份乙型脑炎减毒活疫苗各抽取20批，同一批次疫苗样品随机取样6瓶，3瓶用于病毒基础滴度检测，3瓶用于病毒热稳定性滴度检测。检测方式分别为3瓶单瓶平行检测与3瓶混样检测：单瓶平行检测是从3个单瓶中取样分别检测，所得结果取几何均值；混样检测是从相同的3瓶疫苗中分别取样至适宜的容器中进行混合，再取样进行病毒滴度检测。对采用单瓶平行检测的几何平均滴度值和混样检测滴度值进行配对t检验，判断两者之间的差异是否存在统计学意义。结果  两种滴度检测方式得到的疫苗基础滴度值间的t值为0.72，P值为0.48；热稳定性滴度值间的t值为0.34，P值为0.73。两种检测方式的结果差异无统计学意义。结论  单瓶平行检测与多瓶混样检测方式的差异无统计学意义，均可用于乙型脑炎减毒活疫苗病毒滴度的检测。

Objective  To compare the difference between single-vial parallel testing and multi-vial mixed testing of live attenuated Japanese encephalitis vaccine virus titer, laying a foundation for further improvement of the relevant technical requirements in Chinese pharmacopoeia. Methods  Twenty batches of vaccine were randomly selected from one-dose and five-dose vaccines, respectively, and six bottles of vaccine were randomly selected from each batch, among which, three bottles of vaccine were used for testing of basic virus titer, and the other three bottles were used for testing of virus titer thermal stability. The testing methods included parallel testing of 3 single bottles and mixed testing of 3 bottles. Parallel testing of single bottle was to take samples from 3 single bottles to test them separately and obtain the geometric mean value. Mixed sample testing was to take samples from three bottles of vaccine and mix them in suitable containers. Then the mixed samples were tested for virus titer.Paired t-test was used to determine whether there was statistically significant difference between the titers of single-vial parallel testing and multi-vial mixed testing. Results  With the 2 kinds of titer testing methods used, t value was 0.72 and P value was 0.48 for basic titer, the t value was 0.34 and P value was 0.73 for thermal stability. There was no statistical significance between the two methods. Conclusions  There is no statistical significanly ofdifferent between the results of single-vial parallel testing and multi-vial mixed testing. Both methods can be used to test the viral titer of live attenuated Japanese encephalitis vaccine.