乙型脑炎、麻疹胎传母体抗体的调查

86对母婴血清标本用间接酶联免疫测定法(ELISA)测定了乙型脑炎抗体,118对用血凝抑制(血抑)试验测定了麻疹抗体。结果发现,脐血乙型脑炎抗体阳性率为79.1％,母血为74.4％,几何平均滴度在脐血显著高于母血(t=5.1857,P<0.01),比值为1.2∶1。脐血和母血的麻疹血抑抗体阳性率分别为86.4％及84.8％,几何均值也是前者高于后者(t=4.0349,P<0.01),比值为1.3∶1。 108份婴儿血清标本测定结果显示,0～3个月婴儿乙型脑炎抗体阳性率为35％,4～9个月仅为13％,10个月及以上的婴儿全部阴性。此结果与近年上海市小于1岁组乙型脑炎发病率最高相一致,提示应考虑提早乙型脑炎疫苗的接种年龄。

SEROSURVEY OF MATERNALLY DERIVFD ANTIBODIES AGAINST JAPANESE ENCEPHALITIS AND MEASLES

Eighty-six paired maternal and fetal cord sera were assayed by indirect ELISA method for Japanese encephalitis (JE) antibody and 118 paired serum samples were examined by hemagglutination-inhibltion test for measles antibody. The antibody against JE was positive in 74.4% of maternal sera compared to 79.1% in cord sera, and the geometric mean titer (GMT) of antibody in cord sera was significantly higher (t = 5.185 7,P<0.01)than that in maternal sora with a mean ratio 1.2:1, for measles, the rate of positive antibodies in cord and maternal sera was 86.4% and 84.8% respectively and the GMT of antibody was higher in the former than in the latter (2 = 4.0349, P<0.01). The mean ratio was 1.3:1.108 infants at 0-12 month of age were examined. At 0-3 months of age, 35% were positive for JE antibody, but at 4-9 months of age only 13% were positive. All infants were negative when >10 months of age. The low maternally derived antibody may explain the highest incidence of JE in infants of the youngest age group in Shanghai. Thus, early JE vaccination should be considered.