An Investigation on the Level of Antibodies against Diphtheria in Teen-age People

Objective The target of this analysis was to investigate the level of antibodies against diphtheria in teen-age people，for providing the foundation of diphtheria control and prevention．Meth-ods The investigation site and the samples from teen-age people were selected with random sampling．By means of indirect hemagglutination assay (IHA) the antibodies against diphtheria toxoid were exam-ined．The results were analyzed with statistics methods，including X2 test and F test．Results Of 188 sera from 151 (80.32％) had a significant antbody titer against diphtheria toxoid，in which the geomet-ric mean titer (GMT) was 1／12.2236．In the positive rates of different groups, the most was in 9—11 age group (96.67％)，the lowest was in 12—14 age group (48.78％)；it was higher in the town than in the countries；and it was no different between males and female．Conclusion The level of antibodies against diphtheriae in teen-age people in our city was high enough to prevent diphtheria epidemic．