The goal of this clinical trial is to investigate the safety and tetanus antibody response to a Tdap vaccine in healthy plasma donors. The main question it aims to answer are:

• Is it safe to give this vaccine multiple times over one year to plasma donors since the package insert for this vaccine indicates that it should administered once every 10 years?
• What is the tetanus antibody response over time in these donors after receiving the vaccine multiple times during the study?

Participants will receive a Tdap vaccination every 3 months ±2 weeks for 12 months (5 vaccinations) with a 6 month follow-up after the last vaccination. After obtaining informed consent and screening for eligibility including plasmapheresis donor eligibility, subjects will have other baseline assessments performed and if eligible, will receive the scheduled vaccinations, will be assessed for adverse events (AEs) and have plasma samples collected for antibody titers each month thereafter for 11 months, and then at 1 and 6 months after the last vaccination. As these subjects are participating in a standard donor plasmapheresis donor program, assessments for donor eligibility and routine plasmapheresis will be performed; however, only the data specifically required to meet the objectives of this study will be collected.

Inclusion Criteria:

• Male or female ages 18 to 63 years
• Females of childbearing potential who agree to employ highly effective birth control measures during the study
• Signed the informed consent form (ICF)
• Met all of the criteria required to be a Normal Source Plasma donor
• Subject is not participating in any other immunization program
• Subject has not had a Tdap vaccination in the last 90 days before the first study vaccination

Exclusion Criteria:

• Subject is pregnant
• Subject has a condition or abnormality that in the opinion of the Investigator would compromise the safety of the subject or the quality of the data
• Subject has repeated reactions or hypersensitivity to components in the vaccine
• Subject has history of a severe reaction to any immunization
• Subject has a history of Guillain-Barré Syndrome
• The Investigator concludes that the anticipated vaccination site (deltoid area) is not suitable for AE assessment