What happens when an adult gets infanrix?

Tdap vs dtap. Infanrix is diptheria, tetanus and acellular pertussis and is a vaccine made for 4 and under. Tdap is tetanus, diptheria, and acellular pertussis for 11y of age and older, including adults. There would be no reason an adult should receive dtap instead of tdap. The alternative for an adult would be td.