Objective To conduct antibody surveillance and understand the immunization status among population, develop immunization strategies and provide evidence for evaluating immunization effectly. Methods We investigated the diphtheria and tetanus antibody level of 3510 persons aged 2 - 39 years old in 21 counties of Henan Province during 1998 - 2002, multilevel cluster random sampling method was used in the study. Results The overall positive rates of diphtheria and tetanus antibody were 80.5 % and 77.9 % respectively, for both of them, the highest positive rate was among the children aged 2 - 3 years old, the lowest one was among the adults aged 25 - 39 years old, and the rate among the population living in mountain areas was lower than that among the population living in plain and urban areas. The GMTs of diphtheria and tetanus antibody were 0.101 IU/mL and 0.073IU/mL respectively, for both of them, the highest GMT was among the children aged 8 - 9 years old,the lowest one was among the adults aged 25 - 39 years old. The results suggested that the effect of routine immunization of diphtheria and tetanus toxoid was reliable, but the immunity faded with age increasing then the vaccinated persons became new susceptible persons. Conclusion It is necessary to strengthen the vaccination of diphtheria toxoid to adults in time,and conduct the tetanus toxoid immunization to the child-bearing aged women in neonatal tetanus high-risk counties.
Chinese Journal of Vaccines and Immunization