This disclosure relates to methods for eliciting an immune response against C. difficile toxin A and toxin B in an adult human subject. The subject may be at risk for a primary symptomatic C. difficile infection. In some embodiments, a method is for eliciting an immune response against C. difficile toxin A and toxin B in an adult human subject at risk for a primary symptomatic C. difficile infection, and comprises administering to the subject a composition comprising C. difficile toxoid A and toxoid B at least three times, each administration being about seven days apart.
