Immunogenicity of a Triple Diphtheria-

Background: Immunization against diphtheria, tetanus and pertussis has been applied in Iran since 1950. WHO suggests periodical evaluation of effectiveness of the triple diphtheria-tetanus-whole cell pertussis (DTwP) vaccine, worldwide. Objectives: To determine the immunogenicity of locally manufactured DTwP vaccine administered to preschool children in a number of health centers of Tehran in 2006. Methods: In this prospective study, 350 children aged 4-6 years were injected with DTwP vaccine manu-factured by Razi Institute of Iran. Blood samples were collected before and 2-4 weeks after the vaccination. The immunogenicity of the vaccine was assayed by measurement of specific antibodies using enzyme-linked immunosorbent assay (ELISA) technique. Results: Of the 337 children who were vaccinated, 99.4 % and 100 % had protective anti-diphtheria and anti-tetanus antibody titers, respectively. The vaccine response and seroconversion for pertussis was achieved in 70.3 % of the subjects. The geometric mean titers (GMT) of the antibodies produced against diphtheria, tetanus and pertussis by DTwP vaccine were 7.76, 9.37 IU/ml and 30.20 EU/ml after booster vaccine dose, respectively