Diphtheria, Pertussis, Tetanus, Vaccine-Preventable Diseases
Conditions
Keywords
Safety, Immunogenicity, Immune interference, Pregnant women, Newborns, Infants and young children, Pertussis-containing vaccine, Genetically-detoxified recombinant acellular pertussis vaccine
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.
Detailed description
Pertussis remains a major global public health problem. In Thailand, pertussis vaccination is recommended for all pregnant women at 20-32 weeks' gestation to protect newborns and young infants against pertussis during early life. In addition, combined diphtheria-tetanus-pertussis vaccination is routinely administered as a primary series at 2, 4, and 6 months of age, followed by booster doses at 18 months and 4-6 years of age. TdaP2gen is a combined tetanus, diphtheria, and recombinant genetically detoxified acellular pertussis vaccine, containing 2 µg pertussis antigen, which has been recently developed. Previous clinical studies have demonstrated that TdaP2gen is safe and elicits non-inferior immune responses against pertussis compared with the 5 µg recombinant acellular pertussis vaccine (TdaP5gen) and the chemically inactivated Tdap vaccine. However, as TdaP2gen is a newly licensed vaccine in Thailand, data on its safety, immunogenicity in pregnant women, placental antibody transfer to infants, and potential immune interference with infant responses to routine pertussis-containing vaccines remain limited. Therefore, this study aims to evaluate the safety and immunogenicity of TdaP2gen in pregnant women, assess transplacental antibody transfer to newborns, and investigate its impact on immune responses to diphtheria, tetanus, and pertussis following primary series and booster vaccination up to 15-18 months of age in infants and young children. This study is divided into 3 phases as follows: Phase 1 - Maternal and fetal phase: This phase will evaluate the immunogenicity and safety of TdaP2gen vaccination in pregnant women, including immune responses against tetanus, diphtheria, and pertussis, as well as the transplacental transfer of antibodies to newborns. Phase 2 - Infant phase: This phase will assess immune responses to tetanus, diphtheria, and pertussis in infants following completion of the primary pertussis-containing vaccine series at 2, 4, and 6 months of age, comparing infants who receive whole-cell pertussis-containing vaccines (wP-containing vaccines) with those who receive acellular pertussis-containing vaccines (aP-containing vaccines). Phase 3 - Toddler phase: This phase will evaluate immune responses to tetanus, diphtheria, and pertussis in toddlers after receiving a pertussis-containing booster vaccination at 15-18 months of age, comparing children who receive whole-cell pertussis-containing vaccines (wP-containing vaccines) with those who receive acellular pertussis-containing vaccines (aP-containing vaccines).
Interventions
BIOLOGICALMaternal TdaP2gen vaccine
A combined tetanus toxoid, reduced diphtheria toxoid, reduced-dose (2 µg) genetically-detoxified recombinant acellular pertussis vaccine (TdaP2gen)
BIOLOGICALInfant Acellular Pertussis-containing Vaccine
An infant acellular pertussis (aP)-containing vaccine
BIOLOGICALInfant Whole-cell Pertussis-containing Vaccine
An infant whole-cell pertussis (wP)-containing vaccine
Sponsors
Chiang Mai University
Thailand Center of Excellence for Life Sciences
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Intervention model description
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.
Eligibility
Sex/Gender
ALL
Age
0 Days to 45 Years
Healthy volunteers
Yes
Inclusion criteria
Phase 1: Pregnant women Inclusion Criteria: * 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
Exclusion criteria
* 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 * Acute illness within 4 weeks prior to enrollment * Contraindications to intramuscular vaccination, including thrombocytopenia, coagulation disorders, hemophilia A or B, or use of anticoagulant therapy during pregnancy * Concurrent participation in another clinical study involving investigational vaccines or medications during participation in this study * Any medical or obstetric condition that, in the opinion of the study investigator, may interfere with study assessments or increase the risk to the mother or infant associated with study participation Phase 2: Infants Inclusion Criteria: \- All infants born to pregnant women enrolled in Phase 1 who received TdaP2gen vaccination during pregnancy will be eligible for enrollment to Phase 2 study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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 | Pre-vaccination baseline, 4 weeks after vaccination (+/- 14 days), and at delivery | 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 |
| Phase 1: Cord blood anti-PT, anti-FHA, anti-diphtheria toxoid, and anti-tetanus toxoid IgG geometric mean concentrations and seroresponse rates at birth | At delivery | 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 |
| Phase 1: Incidence of solicited local and systemic adverse events, serious adverse events, and adverse pregnancy outcomes of TdaP2gen vaccination during pregnancy | From vaccination until delivery, assessed up to approximately 22 weeks post-vaccination. | 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. |
| 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 | Pre-primary series vaccination (within 2 months after birth) and post-primary series vaccination (at age 7 months +/- 14 days) | 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 |
| 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 | At 12 months of age (+/- 14 days), pre-booster vaccination, and 1 month after booster vaccination (+/- 14 days) | 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 |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| 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 | Assessment of maternal pertussis-neutralizing antibody geometric mean titers in a subset of 40 pregnant women before TdaP2gen vaccination, after vaccination, and at delivery |
| Phase 1: Cord blood pertussis-neutralizing antibody geometric mean titers at birth | At delivery | Assessment of pertussis-neutralizing antibody geometric mean titers in cord blood samples from newborns of a subset of 40 vaccinated pregnant women at delivery |
| Phase 1: Knowledge and acceptability of pertussis and pertussis vaccine among pregnant women assessed using a structured questionnaire | Pre-vaccination baseline | Assessment of knowledge and acceptability of pertussis and pertussis vaccine among pregnant women using a structured questionnaire |
| 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) | Assessment and comparison of pertussis-neutralizing antibody geometric mean titers in a subset of 40 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 |
| 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 | Assessment and comparison of the frequency and severity of solicited local and systemic adverse events, unsolicited adverse events, and serious adverse events following administration of aP- or wP-containing vaccines during the primary vaccination series in infants born to mothers receiving TdaP2gen vaccine during pregnancy |
| Phase 3: Infant pertussis-neutralizing antibody geometric mean titers following booster diphtheria-tetanus-pertussis vaccination | At 12 months of age (+/- 14 days), pre-booster vaccination, and 1 month after booster vaccination (+/- 14 days) | Assessment and comparison of pertussis-neutralizing antibody geometric mean titers in a subset of 40 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 |
| Phase 3: Incidence of solicited local and systemic adverse events, unsolicited adverse events, and serious adverse events following booster diphtheria-tetanus-pertussis vaccination in infants | From booster vaccination through 28 days after vaccination | Assessment and comparison of the frequency and severity of solicited local and systemic adverse events, unsolicited adverse events, and serious adverse events following administration of aP or wP booster vaccination in infants born to mothers receiving TdaP2gen vaccine during pregnancy |
Countries
Thailand
Contacts
CONTACTTavitiya Sudjaritruk, MD, PhD
PRINCIPAL_INVESTIGATORTavitiya Sudjaritruk, MD, PhD
Department of Pediatrics, Faculty of Medicine, Chiang Mai University
Outcome results
None listed