Objective@#To evaluate the
immunity and influencing factors of
diphtheria among
preschool children in Shenzhen,to provide reference for effective
monitoring of
diphtheria IgG antibody level in
preschool children.@*
Methods@#
Serum samples were collected from 296
preschool children aged 4-6
who were recruited in Shenzhen. The
diphtheria antibody titer in
serum was determined by
enzyme linked immunosorbent assay, and the effect of different immumuzation
schedule including types of
vaccine and
vaccination timing, on the geometric mean concentration (GMC) of
diphtheria IgG antibody and antibody positive rate were analyzed.@*Results@#The GMC of
diphtheria IgG antibody was 0.71 IU/mL, and the positive conversion rate was 33.1%. There were significant differences in antibody GMC and antibody positive conversion rate of
diphtheria in different
age groups( F/χ 2=11.77, 27.45, P < 0.01 ). The GMC and antibody positive conversion rate showed significant differences by
diphtheria antibodies,
vaccine types and end
dose vaccination intervals( F=49.53, 12.95,11.61, P <0.01). There were statistically significant differences in the positive conversion rate of
diphtheria antibodies in
children with different types of
diphtheria antibodies,
vaccine types of
diphtheria antibodies, and
diphtheria antibodies at the
time interval of final
vaccination (Fisher exact
probability method, P <0.01).@*Conclusion@#The overall positive conversion rate of
diphtheria antibody in
preschool children in Shenzhen is high. Timely completion of full
diphtheria vaccination can improve the antibody level and
plays a better
role in protecting
preschool children.