Objective: To determine measles antibody levels and influencing factors among children aged 6 to 15 years in Zhejiang province.
Methods: Blood samples were collected from 2069 children aged 6 to 15 years in Changxing county (Huzhou) and Liandu district (Lishui) of Zhejiang province. Serum level of measles IgG antibody was measured using ELISA, and 800 mIU/mL was applied as the cut-off point of high antibody level. Chi-square or trend Chi-square test was used to analyze difference in positive rates of high antibody level among children with different characters, and the factors related to high antibody level in the vaccinated children were analyzed using multivariate logistic regression.
Results: Among 2069 subjects, positive rate of high measles antibody level was 36.06% (746/2069). Multivariate logistic regression showed that the high measles antibody level was significantly associated with age of children and the age of first measles vaccine inoculation. The positive rate of high measles antibody level decreased with age(OR=0.866, 95%CI:0.830-0.904, P<0.01), and the positive rate in children whose first vaccination at ≥ 12 months of age was higher than those whose first vaccination at 8 months of age(OR=0.633, 95%CI:0.498-0.805, P<0.01).
Conclusions: In order to obtain high measles antibody level and to maintain high levels of population immune barrier, it is suggested that first dose of vaccination can be appropriately delayed in low epidemic areas, and elder children should have timely catch-up vaccination.
目的: 了解浙江省6~15岁儿童抗麻疹病毒高浓度抗体阳性率及其影响因素，为制订麻疹防控策略提供科学依据。
方法: 采集浙江省湖州市长兴县和丽水市莲都区2069名6~15岁儿童的血清，ELISA法定量检测麻疹IgG抗体水平，抗体浓度800 mIU/mL以上为达到高浓度抗体。利用 χ 2检验或趋势 χ 2检验比较不同特征人群麻疹高浓度抗体的阳性率；多因素logistic回归分析麻疹疫苗接种儿童麻疹高浓度抗体的影响因素。
结果: 2069名调查对象中，麻疹高浓度抗体阳性率为36.06%（746/2069）。多因素logistic回归分析结果显示，年龄和起始接种月龄是麻疹疫苗接种儿童麻疹高浓度抗体的影响因素。随着年龄的增长，高浓度抗体阳性率呈现下降趋势（ OR：0.866，95% CI：0.830~0.904， P < 0.01）；12月龄及以上接种者的高浓度抗体阳性率高于8月龄接种者（ OR：0.633，95% CI：0.498~0.805， P < 0.01）。
结论: 为维持高水平人群免疫屏障，建议疫情低发地区可以适当延迟麻疹疫苗首剂次接种时间，并对于大龄儿童适时进行补种。