A Phase 2 interventional study of Tdap in Tetanus, Diphtheria and Acellular Pertussis Vaccination, sponsored by ABO Holdings, Inc.. Completed at 1 site in United States. Open to participants aged 18 Years to 63 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-02.
Sponsored by ABO Holdings, Inc. · Phase 2, Interventional, and Basic science
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:
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.
318 studies on the registry are indexed under Tetanus; 29 are open to participants now.
This study's enrollment of 107 is below the median of 418 across 280 interventional studies indexed under Tetanus.
Browse Tetanus studies →This is the only study on the registry with ABO Holdings, Inc. as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Dose: 0.5 mL; Route: Intramuscular (IM) in the deltoid muscle; Frequency: Every 90 days; Duration: 5 doses over 1 year.
Biological: Tdap
Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine Adsorbed Suspension manufactured by Sanofi Pasteur
Also known as: Adacel
Number of Participants With Treatment Emergent Adverse Events (TEAEs)
An adverse event (AE) is any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. TEAEs are defined as an adverse event occurring after first study treatment. A serious TEAE was defined as an AE that resulted in any of the following outcomes: death; life-threatening; inpatient hospitalization or prolongation of hospitalization; persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, an important medical event that based on appropriate medical judgment may jeopardize the subject and may require medical or surgical intervention to prevent one of the aforementioned outcomes.
Time frame: Up to 18 months
Anti-tetanus Antibody Titers in Participants Over Time
Anti-tetanus antibody titer levels after each vaccination presented at geometric means (GeoMean) over time.
Time frame: Baseline, Month 1, Month 2, Month 3, Month 4, Month 5, Month 6, Month 7, Month 8, Month 9, Month 10, Month 11, Month 12, Month 13, Month 18
Number of Participants With Post Vaccination Anti-tetanus Antibody Range Levels
The numbers and percentages of participants whose post vaccination antibody levels were \<5 IU/mL; ≥5 IU/mL to 10 IU/mL; \>10 IU/mL to 15 IU/mL; and, \>15 IU/mL after each vaccination.
Time frame: Baseline, Month 1, Month 2, Month 3, Month 4, Month 5, Month 6, Month 7, Month 8, Month 9, Month 10, Month 11, Month 12, Month 13, Month 18
Subjects were recruited from the Glassboro, New Jersey area during May through November, 2024, without regard to ethnicity, race, or socioeconomic level. Standard recruiting practices such as IRB-approved flyers were used to recruit study volunteers
| Milestone | Tdap for Plasma Donors |
|---|---|
| Started | 107 |
| Treatment population | 100 |
| Completed | 66 |
| Not completed | 41 |
| Withdrew: Withdrawal by subject | 20 |
| Withdrew: Adverse event | 4 |
| Withdrew: No longer eligible | 4 |
| Withdrew: Lost to follow-up | 6 |
| Withdrew: Screen failure | 7 |
An adverse event (AE) is any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. TEAEs are defined as an adverse event occurring after first study treatment. A serious TEAE was defined as an AE that resulted in any of the following outcomes: death; life-threatening; inpatient hospitalization or prolongation of hospitalization; persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, an important medical event that based on appropriate medical judgment may jeopardize the subject and may require medical or surgical intervention to prevent one of the aforementioned outcomes.
| Participants | Tdap for Plasma Donors |
|---|---|
| Number of Participants With Treatment Emergent Adverse Events (TEAEs) | 36 |
Anti-tetanus antibody titer levels after each vaccination presented at geometric means (GeoMean) over time.
| IU/mL | Tdap for Plasma Donors |
|---|---|
| Screening | 0.3 ± 0.81 |
| Month 1 | 10.7 ± 1.29 |
| Month 2 | 7.4 ± 1.07 |
| Month 3 | 5.5 ± 1.14 |
| Month 4 | 5.9 ± 1.02 |
| Month 5 | 5.2 ± 0.89 |
| Month 6 | 3.9 ± 1.09 |
| Month 7 | 4.8 ± 1.07 |
| Month 8 | 3.7 ± 1.24 |
| Month 9 | 3.1 ± 1.23 |
| Month 10 | 4.7 ± 0.96 |
| Month 11 | 3.2 ± 1.22 |
| Month 12 | 2.9 ± 1.01 |
| Month 13 | 3.4 ± 1.05 |
| Month 18 | 2.3 ± 1.11 |
The numbers and percentages of participants whose post vaccination antibody levels were \<5 IU/mL; ≥5 IU/mL to 10 IU/mL; \>10 IU/mL to 15 IU/mL; and, \>15 IU/mL after each vaccination.
| Participants | Tdap for Plasma Donors |
|---|---|
| Screening — < 5 IU/ mL | 94 |
| Screening — ≥ 5 to 10 IU/ mL | 5 |
| Screening — ≥ 10 to 15 IU/ mL | 0 |
| Screening — ≥ 15 IU/ mL | 0 |
| Month 1 — < 5 IU/ mL | 16 |
| Month 1 — ≥ 5 to 10 IU/ mL | 20 |
| Month 1 — ≥ 10 to 15 IU/ mL | 16 |
| Month 1 — ≥ 15 IU/ mL | 36 |
| Month 2 — < 5 IU/ mL | 23 |
| Month 2 — ≥ 5 to 10 IU/ mL | 29 |
| Month 2 — ≥ 10 to 15 IU/ mL | 12 |
| Month 2 — ≥ 15 IU/ mL | 18 |
| Month 3 — < 5 IU/ mL | 27 |
| Month 3 — ≥ 5 to 10 IU/ mL | 34 |
| Month 3 — ≥ 10 to 15 IU/ mL | 9 |
| Month 3 — ≥ 15 IU/ mL | 8 |
| Month 4 — < 5 IU/ mL | 25 |
| Month 4 — ≥ 5 to 10 IU/ mL | 31 |
| Month 4 — ≥ 10 to 15 IU/ mL | 9 |
| Month 4 — ≥ 15 IU/ mL | 8 |
| Month 5 — < 5 IU/ mL | 27 |
| Month 5 — ≥ 5 to 10 IU/ mL | 33 |
| Month 5 — ≥ 10 to 15 IU/ mL | 5 |
| Month 5 — ≥ 15 IU/ mL | 6 |
| Month 6 — < 5 IU/ mL | 32 |
| Month 6 — ≥ 5 to 10 IU/ mL | 22 |
| Month 6 — ≥ 10 to 15 IU/ mL | 4 |
| Month 6 — ≥ 15 IU/ mL | 3 |
| Month 7 — < 5 IU/ mL | 29 |
| Month 7 — ≥ 5 to 10 IU/ mL | 25 |
| Month 7 — ≥ 10 to 15 IU/ mL | 8 |
| Month 7 — ≥ 15 IU/ mL | 5 |
| Month 8 — < 5 IU/ mL | 35 |
| Month 8 — ≥ 5 to 10 IU/ mL | 19 |
| Month 8 — ≥ 10 to 15 IU/ mL | 5 |
| Month 8 — ≥ 15 IU/ mL | 3 |
| Month 9 — < 5 IU/ mL | 33 |
| Month 9 — ≥ 5 to 10 IU/ mL | 15 |
| Month 9 — ≥ 10 to 15 IU/ mL | 5 |
| Month 9 — ≥ 15 IU/ mL | 1 |
| Month 10 — < 5 IU/ mL | 28 |
| Month 10 — ≥ 5 to 10 IU/ mL | 26 |
| Month 10 — ≥ 10 to 15 IU/ mL | 6 |
| Month 10 — ≥ 15 IU/ mL | 2 |
| Month 11 — < 5 IU/ mL | 38 |
| Month 11 — ≥ 5 to 10 IU/ mL | 21 |
| Month 11 — ≥ 10 to 15 IU/ mL | 5 |
| Month 11 — ≥ 15 IU/ mL | 0 |
| Month 12 — < 5 IU/ mL | 38 |
| Month 12 — ≥ 5 to 10 IU/ mL | 14 |
| Month 12 — ≥ 10 to 15 IU/ mL | 4 |
| Month 12 — ≥ 15 IU/ mL | 0 |
| Month 13 — < 5 IU/ mL | 42 |
| Month 13 — ≥ 5 to 10 IU/ mL | 1 |
| Month 13 — ≥ 10 to 15 IU/ mL | 20 |
| Month 13 — ≥ 15 IU/ mL | 4 |
| Month 18 — < 5 IU/ mL | 48 |
| Month 18 — ≥ 5 to 10 IU/ mL | 15 |
| Month 18 — ≥ 10 to 15 IU/ mL | 0 |
| Month 18 — ≥ 15 IU/ mL | 0 |
Collected over From enrollment until end of follow-up, up to 18 months. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Tdap for Plasma Donors | 0/100 (0%) | 1/100 (1%) | 36/100 (36%) |
| Event | Tdap for Plasma Donors |
|---|---|
| Myocardial infarctionCardiac disorders | 1/100 |
| Event | Tdap for Plasma Donors |
|---|---|
| Injection site painGeneral disorders | 20/100 |
| Injection site swellingGeneral disorders | 9/100 |
| HeadacheNervous system disorders | 9/100 |
| Blood creatinine increasedInvestigations | 7/100 |
| FatigueInvestigations | 7/100 |
| DiscomfortGastrointestinal disorders | 5/100 |
| Age, Categorical(Participants) | Tdap for Plasma Donors |
|---|---|
| <=18 years | 0 |
| Between 18 and 65 years | 100 |
| >=65 years | 0 |
| Sex: Female, Male(Participants) | Tdap for Plasma Donors |
|---|---|
| Female | 21 |
| Male | 79 |
| Race (NIH/OMB)(Participants) | Tdap for Plasma Donors |
|---|---|
| American Indian or Alaska Native | 1 |
| Asian | 2 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 28 |
| White | 66 |
| More than one race | 0 |
| Unknown or Not Reported | 3 |
| Ethnicity (NIH/OMB)(Participants) | Tdap for Plasma Donors |
|---|---|
| Hispanic or Latino | 12 |
| Not Hispanic or Latino | 86 |
| Unknown or Not Reported | 2 |
| Region of Enrollment(Participants) | Tdap for Plasma Donors |
|---|---|
| United States | 100 |
| Baseline Anti-tetanus Antibody Titers(IU/mL) | Tdap for Plasma Donors |
|---|---|
| Geometric mean | 0.3 (0 to 6) |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from May 2023 to primary completion in May 2025, 24 months.
Results were first posted in Jul 2026, 1 year 1 month after primary completion.
Of 11 phase 2 interventional studies under Tetanus, half reached primary completion within 5 months of starting (the median), counting those still running; a quarter within 2 and three quarters within 17. This study's 24 months is above that.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.