The purpose of this study is to evaluate safety of GC3111 and to describe immunogenicity of a single dose of GC3111 versus Boostrix® vaccine among healthy adults in 19 to <65 years of age.

To evaluate immunogenicity of GC3111 as tetanus, diphtheria and acellular pertussis (Tdap) vaccine in healthy adults.

To evaluate safety (solicited adverse events) of GC3111 in healthy adults.

Inclusion Criteria:

• Healthy adults aged between 19 and 64 years at the time of vaccination
• Informed consent and assent forms have been signed and dated

Exclusion Criteria:

• Known or suspected receipt of any Tdap vaccine
• Subject is pregnant, or lactating, or of child bearing potential without using an effective method of contraception or not practicing abstinence
• Receipt of any vaccine within 30 days before receiving study vaccine
• Any condition that, in the opinion of the Investigator, might interfere with the ability to comply with trial procedures.