COMPATIVE IMMUNOGENICITY OF MEASLES VIRUS VACCINE STRAINS

虽然麻疹疫苗自1963年以来就已获得许可， 它是发病率和死亡率的重要原因 特别是在发展中国家。 死亡率最高的原因是 麻疹发生在生命的头两年，病死率最高。 12个月以下儿童的发病率。 推迟麻疹疫苗接种 直到15个月大的时候， 麻疹的发病率继续下降。 之一 早期有效免疫接种的障碍是 被动获得性母源抗体。 因此，有效的麻疹 免疫战略需要及早接种疫苗， 但在母体抗体预期不会 抑制或干扰保护性免疫反应的发展。 为探讨麻疹疫苗株和免疫年龄对麻疹免疫效果的影响， 麻疹疫苗免疫反应的双盲安慰剂对照研究 进行了一项研究，以比较对两种麻疹病毒株的免疫反应 疫苗174名儿童参加了这项研究; 99名儿童接受了高 在6个月时滴度EZ疫苗，75名儿童接受标准剂量的 9个月时接种施瓦茨疫苗。 在接种EZ疫苗的儿童中，97%的儿童 血清阴性儿童和85%的血清阳性儿童表现为 对麻疹病毒的四倍或更高抗体应答，由 空斑减少中和测定。 同样，97%和100%的 血清阳性和血清阴性的儿童，分别接受施瓦茨 疫苗血清转化。 每个疫苗组中超过90%的儿童 在接种后3个月和6个月， 免疫接种后麻疹抗体GMT 施瓦茨疫苗的免疫水平比抗体水平高出两倍 接种EZ疫苗后。 目前，高剂量EZ疫苗 不建议用于幼儿，但这项研究表明， 使用标准的抗病毒药物， 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.