THE IMMUNE RESPONSE TO DIPHTHERIA TOXOID IN CHILDREN VACCINATED WITH DPT VACCINE

Abstract

In this study, 64 blood samples were taken from the healthy children after2-4 weeks of vaccination by DPT. The children were divided into three groupsaccording to the number of the doses of vaccine .The aged of children of thefirst three groups ranging from 6-55 months while the age of the fourth groupranging from 6-12 years, received the fifth dose of vaccine before 2-8 years. Thecontrol group included fifteen healthy children. They were aged between 11-85months and they had not been received DPT vaccine before. Neutralization testwas used to assess the concentration of the diphtheria antitoxin (DAT). Theresults showed that the serum first three groups of children contain aconcentration of DAT higher than 0.1 IU/ml at the percentage 98.4% while theresults of the fourth and control groups showed reduce of the DATconcentration less than 0.1 IU/ml at the percentage 60.86% and 100%respectively. Also the result showed an increase in the concentration of DAT asthe number of the vaccine doses increased. Where the fifth dose showedsignificant differences in DAT concentration (p ≤ 0.001, 0.01, 0.05) incomparison with control, the third and the fourth doses respectively. The resultsshowed negative direct correlation between the age of fourth group and theconcentration of DAT (r= -0.730) and also there was positive direct correlationbetween the number of days after the vaccination and the concentration of DAT(r = 0.532) for the first three groups of the vaccinated children.