Medical Information Only. Consult your healthcare provider before considering clinical trial enrollment.
Diphtheria clinical trials
Every US clinical trial registered for Diphtheria — phase mix, recruiting status, and the sponsors running them, straight from the NIH ClinicalTrials.gov registry.
16 US clinical trials ·
The research picture
Diphtheria has 16 registered US clinical trials; none are currently listed as recruiting, so most are completed or in follow-up.
- 0
- recruiting participants now
- 0%
- of trials open to enrollment
- 12
- in Phase 3–4 (later-stage)
- 5
- top sponsor: Sanofi Pasteur, a Sanofi Company
Counts reflect the public ClinicalTrials.gov registry as last mirrored by PlainTrial. Status and phase are reported by each study's sponsor. This is reference information, not medical advice.
Active & Recent Trials
Post-marketing Safety Study of GSK Biologicals' Boostrix® Vaccine
GlaxoSmithKline
NCT00297856
Immune Response and Safety Comparison of 3 Lots of GSK Biologicals' DTaP-IPV Candidate Vaccine to DTaP + IPV Vaccines
GlaxoSmithKline
NCT00148941
Study of DTap-IPV Compared to DAPTACEL® and IPOL® as the 5th Dose in Children 4 to 6 Years of Age
Sanofi Pasteur, a Sanofi Company
NCT01346293
Study of the Safety, Immunogenicity and Lot Comparability of DAPTACEL When Administered With Other Recommended Vaccine
Sanofi
NCT00662870
Study of Menactra® in Healthy Subjects at 9 Months and Concomitantly With Pentacel® at 15 to 18 Months of Age
Sanofi Pasteur, a Sanofi Company
NCT01659996
US-licensed Combined Vaccine Against Tetanus & Diphtheria, Given With US-licensed Vaccine Against Meningococcal Disease
GlaxoSmithKline
NCT00282295
Evaluation of GlaxoSmithKline Biologicals' Boostrix® Vaccine in Comparison With Decavac™ Vaccine.
GlaxoSmithKline
NCT00835237
Study of Adacel® Vaccine Administered to Persons 10 Years of Age
Sanofi
NCT01311557
Study of DAPTACEL® Administered as a 5th Dose in 4 to 6-Year-Old Children Previously Immunized With PENTACEL™
Sanofi Pasteur, a Sanofi Company
NCT00802867
Post-licensure, Modified Double-blind, Multi-center Study Evaluating Safety and Immunogenicity of ADACEL® and BOOSTRIX®
Sanofi
NCT00319553
Descriptive, Open-label, Multicenter Study of the Safety of Redosing With ADACEL® Vaccine
Sanofi Pasteur, a Sanofi Company
NCT00347958
Immunogenicity of Adacel® and BOOSTRIX® Vaccines in Adolescents
Sanofi Pasteur, a Sanofi Company
NCT01629589
Study on the Safety and Immunogenicity of Boostrix Vaccine in Pregnant Malian Women and Their Infants
National Institute of Allergy and Infectious Diseases (NIAID)
NCT03589768
Pertussis Vaccine in Healthy Pregnant Women
National Institute of Allergy and Infectious Diseases (NIAID)
NCT00707148
PFAS Exposure and Immune Response to Vaccination in Adults
Rutgers, The State University of New Jersey
NCT06588530
Pentavalent DTaP-Hep B-IPV
National Institute of Allergy and Infectious Diseases (NIAID)
NCT00133445
Phase Distribution
| Phase | Trial count |
|---|---|
| Phase 1 | 1 |
| Phase 2 | 2 |
| Phase 3 | 4 |
| Phase 4 | 8 |
Top Sponsors
Source: ClinicalTrials.gov, National Library of Medicine. Data is informational only.
Reading the Diphtheria Trial Landscape
ClinicalTrials.gov lists 16 US studies indexed under Diphtheria, and 0 of those are currently open to recruitment — roughly 0% of the total volume on the registry. That ratio is a useful proxy for activity level: a high share of recruiting studies often signals that research interest is current and that new enrollment opportunities are appearing, while a low share typically means the field is dominated by completed or follow-up work where most participant spots have already been filled. These counts reflect the public registry only and include studies at every stage of design, so they should be read as an index of research attention rather than as a measure of treatment availability.
The phase distribution for Diphtheria shows 12 late-stage studies (Phase 3 and Phase 4 combined) alongside 3 earlier-phase entries (Phase 1 through Phase 2). Phase 1 and Phase 2 studies focus on early safety signals, dosing, and preliminary effect, while Phase 3 studies are typically the larger efficacy and safety trials submitted toward regulatory review, and Phase 4 studies follow approved interventions in real-world use. A condition weighted toward later phases often reflects a mature research pipeline with several interventions already close to or past approval, whereas a heavier early-phase tilt suggests the field is still exploring new mechanisms and candidate approaches.
Top sponsor activity for Diphtheria is led by Sanofi Pasteur, a Sanofi Company with 5 indexed trials, alongside 4 other organizations in the top contributor list. The list on this page surfaces up to 16 of the most relevant recent and active entries, ordered with recruiting studies first so practical options are visible. All figures are derived from the public ClinicalTrials.gov dataset maintained by the National Library of Medicine and are reproduced here for reference. Inclusion of a trial, sponsor, or intervention on this page is neither an endorsement nor a recommendation — eligibility, protocol changes, and site-level status can shift frequently, so always verify current details on ClinicalTrials.gov and consult a qualified healthcare provider before acting on anything you see here.
Frequently Asked Questions
How many clinical trials are there for Diphtheria?
PlainTrial tracks 16 US clinical trials for Diphtheria, of which 0 are currently recruiting participants. Data sourced from ClinicalTrials.gov.
How do I find a recruiting trial for Diphtheria?
Use the trial list above filtered by "Recruiting" status, or visit our trial finder at /recruiting to search by condition and state. Always discuss trial participation with your healthcare provider before enrolling.
Is this data current?
Data is sourced from ClinicalTrials.gov and reflects our most recent data pull. Trial status may have changed since then. Always verify current information at ClinicalTrials.gov before making decisions about participation.
Related
Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from ClinicalTrials.gov (National Library of Medicine). Consult a qualified professional before making decisions based on this data.
Read our methodology — how this data is sourced, computed, and verified.
Source: ClinicalTrials.gov (NIH/NLM) ClinicalTrials.gov AACT registry · 2026 Trial counts and statuses sourced from ClinicalTrials.gov. Sponsor counts include both industry and federal/academic sponsors.