COMPATIVE IMMUNOGENICITY OF MEASLES VIRUS VACCINE STRAINS

虽然麻疹疫苗自1963年以来就已经获得许可，但这种疾病并没有 已被根除，是发病率和死亡率的一个重要原因 尤其是在发展中国家。死亡率最高的是 麻疹发生在生命的头两年，病死率最高 12个月以下儿童的死亡率。推迟接种麻疹疫苗 直到15个月大的这些孩子将允许大量的 麻疹发病率的百分比将继续上升。其中一个 在早期有效免疫的障碍是存在 被动获得母源抗体。因此，一种有效的麻疹 免疫策略需要尽早接种疫苗，以便 在孕妇抗体不被期望的年龄仍然有效 抑制或干扰保护性免疫反应的发展。 为探讨麻疹疫苗株和年龄的免疫效果。 麻疹疫苗免疫应答的双盲安慰剂对照研究 研究比较了对两种麻疹的免疫反应。 疫苗。174名儿童参加了这项研究；99名儿童获得了高 6个月后接种EZ疫苗，75名儿童接种标准剂量的 9个月时接种施瓦茨疫苗。在接种埃博拉疫苗的儿童中，97% 血清阴性儿童和85%的血清阳性儿童表现出 对麻疹病毒的抗体反应是四倍或更高 空斑减少中和试验。同样，97%和100%的 分别接受施瓦茨治疗的血清阳性和血清阴性儿童 疫苗血清转换。每个疫苗组90%以上的儿童 在3个月和6个月后有保护水平的麻疹抗体 尽管免疫后麻疹抗体的GMT 施瓦茨疫苗的抗体水平大约是抗体水平的两倍 在接种EZ疫苗后。目前，大剂量EZ疫苗 不推荐用于幼儿，但这项研究表明 90%的婴儿使用标准疫苗可以达到保护性滴度 9个月时接种施瓦茨疫苗。

Although measles vaccine has been licensed since 1963 the disease has not been eradicated and it is a significant cause of morbidity and mortality especially in developing countries. The highest incidence of death due to measles occurs in the first two years of life with the highest case-fatalit rates in children under 12 months of age. To delay measles vaccination until 15 months of age in these children would allow a substantial percentage of the morbidity due to measles to continue. One of the obstacles to effective immunization at an early age is the presence of passively acquired maternal antibody. Therefore, an effective measles immunization strategy needs to administer vaccine early enough to be effective yet at an age when maternal antibody would not be expected to inhibit or interfere with the development of a protective immune response. In order to investigate the effect of measles strain and age of immunizatio on the immune response to measles vaccine a double-blind placebo controlled study was done to compare the immune response to two strains of measles vaccine. 174 children were enrolled in the study; 99 children received high titered EZ vaccine at 6 months and 75 children received a standard dose of Schwarz vaccine at 9 months. Of the children who received EZ vaccine 97% o the seronegative children and 85% of the seropositive children showed a four-fold or greater antibody response to measles virus as determined by plaque reduction neutralization assay. Similarly, 97% and 100% of the seropositive and seronegative children,respectively, who received Schwarz vaccine seroconverted. Greater than 90% of children in each vaccine group had protective levels of measles antibody at 3 and 6 months after immunization although the GMT of measles antibody following immunization with the Schwarz vaccine was about two fold greater than antibody levels following immunization with the EZ vaccine. Currently, high dose EZ vaccin is not recommended for use in young children, however this study indicates that protective titers can be achieved in >90% of infants using standard Schwarz vaccine at 9 months.