上海市闵行区水痘减毒活疫苗效价监测分析

Monitoring analysis of the titers of varicella attenuated live vaccines in Minhang District, Shanghai

目的了解水痘减毒活疫苗（ varicella attenuated live vaccine, VarV）在不同季节及社区冷链系统各环节中经运输、储存后的效价，评价冷链系统运转状况和疫苗热稳定性，为疫苗管理、引进和研发提供依据。方法在上海市闵行区13家社区中分别随机抽取2012-2013年间水痘暴发罹患率高与低社区各4个，在2013年11月及2014年2、5、8月份分别对入库前、入库后30d的VarV效价进行测定。疫苗效价测定采用定量的蚀斑形成试验计算病毒滴度。结果总疫苗合格率为90．63％，几何平均滴度（geometric mean titer，GMT）为3．67（LgPFU／0．5m1），C公司生产疫苗合格率最高，为96．88％，GMT为3．89（LgPFU／0．5ml）；B公司生产疫苗合格率为91．67％，GMT为3．75（LgPFU／0．5ml）；A公司生产疫苗合格率为80．00％，GMT为3．29（LgPFU／0．5ml）；三者间合格率差异有统计学意义（χ^2=8．288，P=0．016）。距闵行区疾病控制中心近点的社区合格率为91．67％，远及中点均为100％，三者间合格率差异无统计学意义（χ^2=3．441，P=0．179）。B公司及C公司除第三季度外合格率均为100％，第三季度合格率较低，A公司为70．00％，B公司为66．67％，C公司为87．50％，三家公司季度间合格率差异均无统计学意义（χ^2=1．25，P=0．7412；χ^2=6．545，P=0．088；χ^2=6．194，P=0．103）。三家公司疫苗效价在入库前、入库后30d合格率差异均无统计学意义（χ^2=0．625，P=0．347；χ^2=0．000，P=1．000；χ^2=2．065，P=0．492）。结论闵行区在疫苗的储存、运输等环节中冷链系统管理、运转良好，C公司疫苗热稳定性优于其他两家公司，A公司疫苗效价还需加大监测力度进一步观察疫苗效价。

Objective To measure the titers of varicella live attenuated vaccines （VarV） during the process of transportation and storage in different seasons and communities of Minhang Distract, Shanghai, to evaluate the operation of cold chain system and the thermal stability of vaccines and to provide references for the management, introduction, research and development of vaccine in future. Methods Four communities with high outbreak rates of varicella during 2012 to 2013 and four communities with low outbreak rates were randomly selected from 13 communities in Minhang District, Shanghai. The titers of VarVs were detected by using the quantitative plaque assay before and after 30 days of storage in November 2013 and February, May, August 2014. Results The overall rate of qualified VarVs was 90.63% with a geometric mean titer （GMT） of 3.67 （ LgPFU/0.5 ml）. 96.88% of the VarVs produced by company C met the quality standard with a GMT of 3.89 （LgPFU/0.5 ml） followed by those produced by company B with a rate of 91.67% and a GMT of 3.75 （ LgPFU/0.5 ml）. The rate of qualified VarVs produced by company A was the lowest, which was 80.00% , with GMT of 3.29 （LgPFU/0.5 ml）. There were significant differences in the rates of qualified VarV among the three companies （χ^2 =8. 288, P=0. 016）. The rate of qualified vaccines in communities close to the Shanghai Minhang Center for Disease Control and Prevention （Minhang CDC） was 91.67%, while 100% of the vaccine samples collected form the communities at a middling distance from or far from the Minhang CDC met the quality standard. No significant difference in the rate of qualified vaccine was found among the three types of communities （χ^2= 3. 441, P= 0. 179）. The quarterly rates of qualified vaccines produced by B and C companies were 100% except for the third quarter. The rates of qualified vaccines produced by A, B and C companies in the third quarter were respectively 70.00% , 66.67% and 87.50%. No statistical differences in the quarterly rates of qualified vaccines were found among the three companies （ χ^2 = 1.25, P = 0.7412 ;χ^2 = 6. 545, P = 0. 088 ;χ^2 = 6. 194, P = 0. 103 ）. No statistical differences in the rates of qualified vaccines before and after 30 days of storage were found among the three companies （ X2 = 0. 625, P = 0.347 ;χ^2= 0. 000, P = 1. 000 ; χ^2 = 2. 065, P = 0. 492）. Conclusion A well-managed and-operated cold chain system was implemented in Minhang District in the storage and transport of vaccines as well as other related links. The thermal stability of vaccines produced by company C was better than those of the other two companies. A surveillance for the titers of vaccines produced by company A should be strengthened.