Survey of the diphtheria and tetanus antibody level among the healthy population in Linyi City

Objective To conduct antibody surveillance and understand the immunization status among the population, develop immunization strategies and provide evidence for evaluating immunization effect.Methods We investigated the diphtheria and tetanus antibody level of 847 persons aged 0-39 years old in 10 counties of Linyi City during 2001-2004, multilevel cluster random sampling method was used in the study.Results The overall positive rates of diphtheria and tetanus antibody were 77.80% and 74.03% respectively, for both of them, the highest positive rate was among the children aged 0-4 years old, the lowest one was among the adults aged 20-39 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 GMC of diphtheria and tetanus antibody were 0.0997 IU/ml and 0.0674 IU/ml respectively, for both of them, the highest GMC was among the children aged 8-10 years old, the lowest one was among the adults aged 20-39 years old. Conclusion The results suggested that the effect of routine immunization of diphtheria and tetanus toxoid was reliable, but the immunity faded with age increasing then vaccinated persons became new susceptible persons. It is necessary to strengthen the vaccination of diphtheria toxoid to adults in time, and conduct the tetanus toxoid immunization to the child-bearing age women in the counties of tetanus high-risk for neonate.