A Comprehensive Monograph on ADT™ Booster (Diphtheria and Tetanus Vaccine, Adsorbed; Seqirus)

I. Executive Summary

ADT™ Booster is a combined, adsorbed vaccine providing booster immunization against diphtheria and tetanus. Sponsored in Australia by Seqirus Pty Ltd, a subsidiary of CSL, and manufactured by AJ Vaccines A/S in Denmark, this vaccine is formulated with reduced antigen content, specifically for re-vaccination purposes. Its primary indication is for children aged five years and older and adults who have previously completed a primary immunization course against both diseases. The vaccine is not intended for primary immunization. Each 0.5 mL dose contains no less than 2 International Units (IU) of diphtheria toxoid and no less than 20 IU of tetanus toxoid, adsorbed onto an aluminium hydroxide adjuvant to enhance immunogenicity.

The vaccine's mechanism of action is based on the well-established principle of toxoid-induced immunity, whereby it stimulates the production of neutralizing antibodies against the toxins produced by Corynebacterium diphtheriae and Clostridium tetani, rather than the bacteria themselves. The clinical efficacy of diphtheria and tetanus toxoids is not derived from modern, large-scale clinical trials, which would be unethical to conduct. Instead, efficacy is inferred from decades of epidemiological data and the consistent achievement of seroprotective antitoxin levels in vaccinated individuals. A complete primary series is considered to confer near-universal protection.