1. A booster dose of tetanus and diphtheria toxoid–containing vaccine should be given to adults who completed a primary series 10 or more years previously.

2. In some countries, a booster dose is also offered between 12 and 18 months of age.

3. Those young children who have not received a booster dose of vaccine in more than a year should receive an injection upon exposure.

4. Conclusion The percentage of seroconversion was less than 100%. A booster dose is required for those seronegative individuals.

5. To compare the impact of three strategies for delivering a booster dose of adult-formulated tetanus–diphtheria–pertussis (Tdap) vaccine to adolescents in Australia.