Maternal Immunization With Tetanus Toxoid, Reduced Diphtheria Toxoid, Reduced-dose (2 µg) Recombinant Pertussis Vaccine (TdaP2gen) and Its Effect on the Immune Response in Thai Infants up to 15-18 Months Old

NCT07621341 | Not Yet Recruiting Phase 4

• 1 other identifier: PED-2569-0103
• Study Type: interventional
• Target: 320
• Locations: 1 country
• Sites: 1

Brief Summary

Pertussis remains a major global public health problem. In Thailand, pertussis vaccination is recommended during pregnancy at 20-32 weeks' gestation, together with routine childhood diphtheria-tetanus-pertussis vaccination administered as a primary series at 2, 4, and 6 months and booster doses at 18 months and 4-6 years of age. TdaP2gen, a newly developed combined tetanus, diphtheria, and recombinant genetically detoxified acellular pertussis vaccine containing 2 µg pertussis antigen, has shown favorable safety and non-inferior immunogenicity compared with existing pertussis vaccines. However, data on its use in pregnant women, transplacental antibody transfer, and potential immune interference in infants remain limited. This study aims to evaluate the safety and immunogenicity of TdaP2gen in pregnant women, assess antibody transfer to newborns, and investigate immune responses to tetanus, diphtheria, and pertussis following primary and booster pertussis-containing vaccinations in infants and toddlers, including comparisons between whole-cell and acellular pertussis-containing vaccine schedules.

Conditions

Pertussis; Diphtheria; Tetanus; Vaccine-Preventable Diseases

Keywords

Safety; Immunogenicity; Immune interference; Pregnant women; Newborns; Infants and young children; Pertussis-containing vaccine; Genetically-detoxified recombinant acellular pertussis vaccine

Outcome Measures

Primary Outcomes (5)

• Phase 1: Maternal anti-pertussis toxin (PT), anti-filamentous hemagglutinin (FHA), anti-diphtheria toxoid, and anti-tetanus toxoid immunoglobulin G (IgG) geometric mean concentrations and seroresponse rates following TdaP2gen vaccination during pregnancy

  Assessment of maternal anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates before TdaP2gen vaccination, after vaccination, and at delivery

  Pre-vaccination baseline, 4 weeks after vaccination (+/- 14 days), and at delivery

• Phase 1: Cord blood anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates at birth

  Assessment of anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates in cord blood collected at delivery among infants born to TdaP2gen vaccinated mothers

  At delivery

• Phase 1: Incidence of solicited local and systemic adverse events, serious adverse events, and adverse pregnancy outcomes of TdaP2gen vaccination during pregnancy

  Assessment of solicited local and systemic adverse events as well as serious adverse events and adverse pregnancy outcomes among pregnant women receiving TdaP2gen vaccination during pregnancy.

  From vaccination until delivery, assessed up to approximately 22 weeks post-vaccination.

• Phase 2: Infant anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates following primary diphtheria-tetanus-pertussis vaccination series

  Assessment and comparison of anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates between infants born to mothers receiving TdaP2gen vaccine during pregnancy who are randomized to receive either aP- or wP-containing vaccines as the primary vaccination series during infancy

  Pre-primary series vaccination (within 2 months after birth) and post-primary series vaccination (at age 7 months +/- 14 days)

• Phase 3: Infant anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates following booster diphtheria-tetanus-pertussis vaccination

  Assessment and comparison of anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates between infants born to mothers receiving TdaP2gen vaccine during pregnancy who previously received either aP or wP-containing vaccines during the primary vaccination series and subsequently receive booster vaccination at 15-18 months of age

  At 12 months of age (+/- 14 days), pre-booster vaccination, and 1 month after booster vaccination (+/- 14 days)

Secondary Outcomes (7)

• Phase 1: Maternal pertussis-neutralizing antibody geometric mean titers following TdaP2gen vaccination during pregnancy

  Pre-vaccination baseline, 4 weeks after vaccination (+/- 14 days), and at delivery

• Phase 1: Cord blood pertussis-neutralizing antibody geometric mean titers at birth

  At delivery

• Phase 1: Knowledge and acceptability of pertussis and pertussis vaccine among pregnant women assessed using a structured questionnaire

  Pre-vaccination baseline

• Phase 2: Infant pertussis-neutralizing antibody geometric mean titers following primary diphtheria-tetanus-pertussis vaccination series

  Pre-primary series vaccination (within 2 months after birth) and post-primary series vaccination (at age 7 months +/- 14 days)

• Phase 2: Incidence of solicited local and systemic adverse events, unsolicited adverse events, and serious adverse events following the primary diphtheria-tetanus-pertussis vaccination series in infants

  From the first dose of the primary diphtheria-tetanus-pertussis vaccination series until 1 month after completion of the primary vaccination series, assessed up to approximately 5 months

Study Arms (3)

Phase 1: Maternal TdaP2gen Group

EXPERIMENTAL

Maternal TdaP2gen Group

Biological: Maternal TdaP2gen vaccine

Phase 2: Infant Acellular Pertussis-containing Vaccine Group

EXPERIMENTAL

Infant Acellular Pertussis-containing Vaccine Group

Biological: Infant Acellular Pertussis-containing Vaccine

Phase 2: Infant Whole-cell Pertussis-containing Vaccine Group

ACTIVE COMPARATOR

Infant Whole-cell Pertussis-containing Vaccine Group

Biological: Infant Whole-cell Pertussis-containing Vaccine

Interventions

Maternal TdaP2gen vaccine BIOLOGICAL

A combined tetanus toxoid, reduced diphtheria toxoid, reduced-dose (2 µg) genetically-detoxified recombinant acellular pertussis vaccine (TdaP2gen)

Phase 1: Maternal TdaP2gen Group

Infant Acellular Pertussis-containing Vaccine BIOLOGICAL

An infant acellular pertussis (aP)-containing vaccine

Phase 2: Infant Acellular Pertussis-containing Vaccine Group

Infant Whole-cell Pertussis-containing Vaccine BIOLOGICAL

An infant whole-cell pertussis (wP)-containing vaccine

Phase 2: Infant Whole-cell Pertussis-containing Vaccine Group

Eligibility Criteria

• Age: 0 Days - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Pregnant women aged 20 to 45 years
• Healthy women in good general health
• Gestational age between 20 and 32 weeks at enrollment
• Singleton pregnancy
• Low-risk, uncomplicated pregnancy as assessed by an obstetrician
• No evidence of congenital anomalies identified on prenatal ultrasonographic screening
• Willing to receive TdaP2gen vaccination and comply with collection of biological specimens as specified in the study protocol
• Willing to allow their infant to receive either whole-cell pertussis-containing or acellular pertussis-containing combination vaccines according to the study randomization process, and to allow collection of biological specimens from the infant as specified in the study protocol
• Able and willing to provide written informed consent prior to study participation

You may not qualify if:

• Receipt of a tetanus-, diphtheria-, and chemical-detoxified pertussis-containing vaccine within 1 year prior to enrollment, or receipt of a tetanus-, diphtheria-, and genetic-detoxified pertussis-containing vaccine (TdaPgen) or genetic-detoxified acellular pertussis vaccine (aPgen) within 2 years prior to enrollment, including during the current pregnancy
• History of laboratory-confirmed or clinically diagnosed pertussis infection within 1 year prior to enrollment
• Presence of underlying medical conditions that may affect study outcomes, including but not limited to malignancy, autoimmune disease, immunodeficiency, epilepsy, hypertension, renal disease, or liver disease, as determined by the investigators
• Pregnancy complications including hypertension (blood pressure \>140/90 mmHg with proteinuria, or \>150/100 mmHg regardless of proteinuria), current antihypertensive treatment, or preeclampsia
• Endocrine disorders including hyperthyroidism, untreated hypothyroidism, or impaired glucose tolerance (e.g., type 1 or type 2 diabetes mellitus) diagnosed before or during pregnancy requiring treatment beyond dietary control
• Severe or progressive neurological disorders, including epilepsy or a history of Guillain-Barré syndrome
• Receipt of immunosuppressive agents, immunomodulatory agents, or high-dose systemic corticosteroids (\>2 mg/kg/day, \>20 mg/day, or equivalent) for more than 14 consecutive days within 6 months prior to enrollment
• History of stillbirth, neonatal death, or recurrent spontaneous abortion (≥3 episodes).
• Current medical or surgical treatment for prevention of preterm labor during the current pregnancy
• Receipt of blood products, blood components, or immunoglobulins within 6 months prior to enrollment
• Receipt of live attenuated vaccines within 3 months or any other vaccines within 28 days prior to enrollment
• History of hypersensitivity or adverse reactions to study vaccines or vaccine components, or history of severe allergic reactions such as anaphylaxis to any vaccine
• Behavioral, cognitive, or psychiatric conditions that, in the opinion of the investigator, may interfere with study participation or protocol compliance
• History of smoking, alcohol abuse, or intravenous drug use that, in the opinion of the investigator, may interfere with study assessments or outcomes
• Fever (body temperature ≥38.0°C or equivalent) within 72 hours prior to enrollment

Sponsors & Collaborators

• Chiang Mai University: lead
• Thailand Center of Excellence for Life Sciences: collaborator

Study Sites (1)

Department of Pediatrics, Faculty of Medicine, Chiang Mai University

Chiang Mai, 50200, Thailand

Location

Related Publications (2)

• Chokephaibulkit K, Puthanakit T, Chaithongwongwatthana S, Bhat N, Tang Y, Anugulruengkitt S, Chayachinda C, Anuwutnavin S, Lapphra K, Rungmaitree S, Tawan M, Andi-Lolo I, Holt R, Fortuna L, Kerdsomboon C, Yuwaree V, Mansouri S, Thai PH, Innis BL. Effective and safe transfer of maternal antibodies persisting two months postpartum following maternal immunization with different doses of recombinant pertussis-containing vaccines. Vaccine. 2024 Jan 12;42(2):383-395. doi: 10.1016/j.vaccine.2023.11.042. Epub 2023 Dec 7.

  PMID: 38061956 BACKGROUND

• Puthanakit T, Chokephaibulkit K, Anugulruengkitt S, Chaithongwongwatthana S, Phongsamart W, Wittawatmongkol O, Rungmaitree S, Tang Y, Kerdsomboon C, Yuwaree V, Fortuna L, Mansouri S, Pham HT, Bhat N, Innis BL. Infant Responses to Primary Immunization Following Vaccination in Pregnancy With Varying Doses of Recombinant Acellular Pertussis Vaccine Alone or Combined With Tetanus-Diphtheria. Pediatr Infect Dis J. 2025 Feb 1;44(2S):S56-S60. doi: 10.1097/INF.0000000000004609. Epub 2025 Feb 14.

  PMID: 39951076 BACKGROUND

MeSH Terms

Conditions

Whooping Cough; Diphtheria; Tetanus; Vaccine-Preventable Diseases

Condition Hierarchy (Ancestors)

Bordetella Infections; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Corynebacterium Infections; Actinomycetales Infections; Gram-Positive Bacterial Infections; Clostridium Infections

Study Officials

• Tavitiya Sudjaritruk, MD, PhD

  Department of Pediatrics, Faculty of Medicine, Chiang Mai University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Tavitiya Sudjaritruk, MD, PhD

CONTACT

+66-53-936471; tavitiya.s@cmu.ac.th

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: This is a multi-stage maternal-infant interventional study. Phase 1 consists of an open-label, single-arm intervention phase enrolling 160 pregnant women receiving TdaP2gen vaccine. Infants born to enrolled mothers subsequently enter Phase 2, a parallel-group, open-label randomized controlled phase evaluating immune responses following the routine primary series of diphtheria-tetanus-pertussis vaccination during infancy using either whole-cell pertussis (wP)-containing or acellular pertussis (aP)-containing vaccines. In Phase 3, infants enrolled in Phase 2 continue in a longitudinal observational follow-up phase assessing immune responses after receiving booster diphtheria-tetanus-pertussis vaccination with either wP-containing or aP-containing vaccines at 15-18 months of age.

Study Record Dates

• First Submitted: May 20, 2026
• First Posted: June 2, 2026
• Study Start: May 26, 2026
• Primary Completion (Estimated): December 31, 2029
• Study Completion (Estimated): December 31, 2030
• Last Updated: June 2, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

TH (1)