Caused by Corynebacterium diphtheriae toxin vaccines against diphtheria immunization of children with diphtheria toxoid is now universal in most of the countries of the world .except in rare circumstances ,Diphtheria toxoid is no longer administrated as a single antigen but is combined with tetanus toxoid and Bordetella pertussis vaccine .The combined form is designated as DPT or triple vaccine .The tetanus and diphtheria toxoid are often adsorbed on insoluble aluminum salts .The B .pertussis component act as adjuvant and enhances the antitoxin response to both toxoids .Different schedules have been recommended in different countries but all aim at attaining level of 0.001 unit / of antitoxin which is considered adequate protection against infection with a toxigenic strain of C. diphtheriae
Immunization schedules for DPT vaccines
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Dose
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Age
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United kingdom
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United state
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WHO
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1
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3 months
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2months
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6 weeks
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2
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4.5 -5 months
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4 months
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10 weeks
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3
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8.5-11 months
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6 months
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14 weeks
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4
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-
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15 months
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-
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Booster
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School entry only DT
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4-6 years
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-
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Diphtheria toxoid this prepared from diphtheria toxin liberated by standard strain of Corynebacterium diphtheriae (PW8) by detoxifiying the toxin with formaldehyde .Single human dose of diphtheria toxoid contains no more than 30 LF of toxoid preservative (other than phenol ) can be added if vaccine is to be dispensed in multidose containers ,and an adjuvant (aluminum or calcium compounds ) is generally used as amineral carrier with concentration of aluminium not exceeding 1.25 mg and that of calicium 1.3 mg per single human dose .
Storage :
The diphtheria toxoid should not be frozen and storage at 2-8 C has been found to be satisfactory .Once frozen ,this toxoid should not be used .The presence of granular or flaky particlesin the vaccine or the formation of deposit below a column of transparent fluid within 30 minutes of shaking is an indication that the vaccine has been frozen
Dose and dose schedules
Single dose is of 0.5 ml injected subcutaneously or intramuscula