Gans H A, Arvin A M, Galinus J, Logan L, DeHovitz R, Maldonado Y
Department of Pediatrics, Stanford University School of Medicine, Calif 94305-5208, USA.
JAMA. 1998 Aug 12;280(6):527-32. doi: 10.1001/jama.280.6.527.
Measles causes serious morbidity in infants, with the highest risk among those who are 6 to 12 months of age. In the United States, measles vaccine has been given at age 12 to 15 months to minimize interference by passive antibodies and to achieve the high seroprevalence required for herd immunity. Infants of mothers with vaccine-induced immunity may lose passively acquired antibodies before 12 months, leaving them susceptible to measles infection.
To assess the immunogenicity of measles vaccine in infants younger than 12 months.
Cohort study conducted before and after measles immunization.
Pediatric clinic in Palo Alto, Calif.
Infants 6 (n = 27), 9 (n = 26), and 12 (n = 34) months of age were enrolled; 72 provided both initial and follow-up samples.
Evaluation of immunogenicity before and 12 weeks after measles vaccination, including measles neutralizing antibody titers, measles-specific T-cell proliferation, and cytokine profiles.
Measles neutralizing antibodies were present before vaccination in 52% (12/23), 35% (7/20), and 0% (0/22) of 6-, 9-, and 12-month-old infants, respectively. In the absence of detectable passive antibodies, geometric mean titers after vaccination were significantly lower in 6-month-old infants compared with 9-month-old infants (27 vs 578, P = .01) and 12-month-old infants (27 vs 972, P=.001). The seroconversion rate, defined as a 4-fold rise in antibody titer, in these 6-month-old infants was only 67%, and only 36% of these infants achieved seroprotective neutralizing antibody titers of 120 or higher after vaccination compared with 100% of 9- and 12-month-old infants lacking detectable passive antibody prior to vaccination. T-cell proliferation and cytokine responses to measles did not differ with age.
Humoral immunity was deficient in 6-month-old infants given measles vaccine, even in the absence of detectable passively acquired neutralizing antibodies. Comparison of their responses with those of 9- and 12-month-old infants indicates that a developmental maturation of the immune response to measles may occur during the first year of life, which affects the immunogenicity of measles vaccine.
麻疹可导致婴儿出现严重发病情况，6至12月龄婴儿的风险最高。在美国，麻疹疫苗接种时间为12至15月龄，以尽量减少被动抗体的干扰，并实现群体免疫所需的高血清阳性率。母亲具有疫苗诱导免疫力的婴儿可能在12月龄前失去被动获得的抗体，从而易患麻疹感染。
评估12月龄以下婴儿接种麻疹疫苗的免疫原性。
在麻疹免疫接种前后进行队列研究。
加利福尼亚州帕洛阿尔托的儿科诊所。
纳入6月龄（n = 27）、9月龄（n = 26）和12月龄（n = 34）的婴儿；72名婴儿提供了初始和随访样本。
评估麻疹疫苗接种前和接种后12周的免疫原性，包括麻疹中和抗体滴度、麻疹特异性T细胞增殖和细胞因子谱。
6月龄、9月龄和12月龄婴儿接种疫苗前分别有52%（12/23）、35%（7/20）和0%（0/22）存在麻疹中和抗体。在未检测到被动抗体的情况下，6月龄婴儿接种疫苗后的几何平均滴度显著低于9月龄婴儿（27对578，P = 0.01）和12月龄婴儿（27对972，P = 0.001）。这些6月龄婴儿中，抗体滴度呈4倍升高的血清转化率仅为67%，接种疫苗后只有36%的婴儿达到120或更高的血清保护性中和抗体滴度，而接种疫苗前未检测到被动抗体的9月龄和12月龄婴儿这一比例为100%。T细胞增殖和对麻疹的细胞因子反应在各年龄组之间无差异。
即使未检测到被动获得的中和抗体，6月龄婴儿接种麻疹疫苗后的体液免疫仍不足。将他们的反应与9月龄和12月龄婴儿的反应进行比较表明，生命第一年可能会出现对麻疹免疫反应的发育成熟，这会影响麻疹疫苗的免疫原性。
