Markowitz L E, Albrecht P, Rhodes P, Demonteverde R, Swint E, Maes E F, Powell C, Patriarca P A
National Immunization Program, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Pediatrics. 1996 Jan;97(1):53-8.
In the United States, younger women are more likely to have immunity to measles from vaccination and are less likely to have been exposed to the wild virus than are older women. To evaluate changes in measles antibody titers in women in the United States and children's responses to measles vaccination, we analyzed data from a measles vaccine trial.
Sera collected from children before vaccination at 6, 9, or 12 months of age and from their mothers were assayed for measles antibodies by plaque reduction neutralization. Responses to vaccination with Merck Sharp & Dohme live measles virus vaccines at 9 months (Attenuvax) and 12 months (M-M-R II) were also analyzed.
Among women born in the United States (n = 614), geometric mean titers (GMTs) of measles antibodies decreased with increasing birth year. For those born before 1957, 1957 through 1963, and after 1963, GMTs were 4798, 2665, and 989, respectively. Among women born outside of the United States (n = 394), there were no differences in GMTs by year of birth. Children of younger women born in the United States were less likely than those of older women to be seropositive at 6, 9, or 12 months. The response to the vaccines varied by maternal birth year for children of women born in the United States. Among 9-month-old children, 93% of those whose mothers were born after 1963 responded, compared with 77% and 60% of those whose mothers were born in 1957 through 1963 and before 1957, respectively. Among 12-month-old children, 98% of those born to the youngest mothers responded, compared with 90% and 83% of those whose mothers were born in 1957 through 1963 and before 1957. The responses of children of women born outside of the United States were not associated with maternal year of birth.
An increasing proportion of children in the United States will respond to the measles vaccine at younger ages because of lower levels of passively acquired maternal measles antibodies.
在美国，年轻女性通过接种疫苗获得麻疹免疫力的可能性更大，且接触野生病毒的可能性低于年长女性。为评估美国女性麻疹抗体滴度的变化以及儿童对麻疹疫苗的反应，我们分析了一项麻疹疫苗试验的数据。
采集6、9或12月龄儿童接种疫苗前及其母亲的血清，采用蚀斑减少中和试验检测麻疹抗体。还分析了9月龄（Attenuvax）和12月龄（M-M-R II）接种默克公司活麻疹病毒疫苗后的反应。
在美国出生的女性（n = 614）中，麻疹抗体的几何平均滴度（GMT）随出生年份的增加而降低。对于1957年以前、1957年至1963年以及1963年以后出生的女性，GMT分别为4798、2665和989。在美国以外出生的女性（n = 394）中，按出生年份划分的GMT没有差异。在美国出生的年轻女性的孩子在6、9或12月龄时血清学阳性的可能性低于年长女性的孩子。美国出生的女性的孩子对疫苗的反应因母亲的出生年份而异。在9月龄儿童中，母亲在1963年以后出生的儿童中有93%有反应，而母亲在1957年至1963年出生的儿童中这一比例为77%，母亲在1957年以前出生的儿童中这一比例为60%。在12月龄儿童中，最年轻母亲所生孩子中有98%有反应，而母亲在1957年至1963年出生的儿童中这一比例为90%，母亲在1957年以前出生的儿童中这一比例为83%。在美国以外出生的女性的孩子的反应与母亲的出生年份无关。
由于被动获得的母体麻疹抗体水平较低，美国越来越多的儿童将在更小的年龄对麻疹疫苗产生反应。
