OBJECTIVETo determine measles antibody levels and influencing factors among children aged 6 to 15 years in Zhejiang province.

METHODSBlood 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.

RESULTSAmong 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(=0.866, 95%:0.830-0.904, <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(=0.633, 95%:0.498-0.805, <0.01).

CONCLUSIONSIn 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.