ABSTRACT
Objective:To assess the antibody persistence 3-5 years following vaccination of measles and rubella combined live-attenuated vaccine (MR) at 8 months of age and measles, mumps and rubella combined attenuated live vaccine (MMR) at 18 months of age.Methods:In 2016, 18-month-old children who were vaccinated with one dose of MR vaccine at the age of 8 months were recruited in Hebei Province as group 1; 4-, 5- and 6-year-old children who were vaccinated with one dose of MR vaccine at the age of 8 months and one dose of MMR vaccine at 18 months of age were recruited in Shanxi, Inner Mongolia and Beijing as group 2, group 3 and group 4, respectively. Serum samples were collected to detect IgG antibodies against measles, mumps and rubella by ELISA. Geometric mean concentrations (GMCs) of measles, mumps, and rubella antibodies were compared among groups by analysis of variance or non-parametric test. Seropositive rates were compared among groups by Chi-square test or Fisher′s exact test. Results:A total of 650 children were included in this study. Seropositive rates of measles, mumps and rubella antibodies 30 d after vaccination of 150 18-month-old children with one dose of MMR vaccine were 100%, 91.33% and 100%, respectively, and the GMCs were 1 846.87 mIU/ml, 299.91 IU/ml and 111.33 IU/ml, respectively. Seropositive rates of measles, mumps and rubella antibodies 3-5 years after vaccination one dose of MR vaccine at 8 months of age and one dose of MMR vaccine at 18 months of age were above 94%, 79% and 71%, respectively, and the GMCs were above 830 mIU/ml, 240 IU/ml and 31 IU/ml. No significant difference in the seropositive rates of the three antibodies was observed among groups 2, 3 and 4 ( P>0.05). There was no significant difference in the GMCs of measles or mumps antibodies among the three groups ( P>0.05), but the differences in the GMCs of rubella antibodies were statistically significant ( P=0.034). Conclusions:Measles, mumps and rubella antibodies persisted for 3-5 years without significant decrease after vaccination one dose of MR vaccine at 8 months of age and one dose of MMR vaccine at 18 months of age.