A Phase 4 interventional study of Triaxis® (Pertussis-containing vaccine) and Vaxelis® (Pertussis-containing vaccine) in Vaccination; Infection, Maternal-Fetal Relations and Pertussis, sponsored by Centre Hospitalier Universitaire Saint Pierre. Completed at 1 site in Belgium. Open to participants aged 2 Months to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-01-13.
Sponsored by Centre Hospitalier Universitaire Saint Pierre · Phase 4, Interventional, and Basic science
The overall objective of the project is to identify the determinants of antibody-mediated immunity in infants born to mothers immunized during pregnancy. Using maternal pertussis immunization as a model, the project will identify key predictors and potential determinants of vaccine responses in pregnant women, of the transfer of maternal antibodies to the newborn and of vaccine responses in infants. A systems biology approach will be used to delineate pre-vaccination and post-vaccination cellular and molecular correlates of the immune response to pertussis immunization in peripheral blood and in breastmilk.
The overall objective of the project is to identify the determinants of antibody-mediated immunity to pertussis in infants born to mothers immunized during pregnancy. Three specific objectives will be targeted:
To reach these objectives, 40 non-pregnant and 80 pregnant women will be recruited into the study and vaccinated with a single dose of a pertussis containing vaccine (Triaxis). Blood samples will be collected from:
At delivery, a placenta fragment will be collected.
In addition, infants 2-3 months old born either from mothers who were not vaccinated against pertussis during pregnancy (n=40) or born from mothers who were vaccinated against pertussis during pregnancy (n=80) will be recruited in the study. Infants will be vaccinated with three doses of a pertussis containing vaccine (Vaxelis), each one month apart starting from 2-3 months of age. Blood samples will be collected from:
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This study's enrollment of 200 is above the median of 120 across 4,200 interventional studies indexed under Infections.
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Exclusion Criteria:
For pregnant and non-pregnant women
For pregnant women
For infants:
Pregnant women will receive one dose of Pertussis-containing vaccine during pregnancy.
Biological: Triaxis® (Pertussis-containing vaccine)
Non-Pregnant women will receive one dose of Pertussis-containing vaccine.
Biological: Triaxis® (Pertussis-containing vaccine)
Infants whose mothers have been immunized during pregnancy with Tdap vaccine. Infants will receive three doses of Pertussis-containing vaccine (with 28 days interval starting at two months of age).
Biological: Vaxelis® (Pertussis-containing vaccine)
Infants whose mothers have not been immunized during pregnancy with Tdap vaccine. Infants will receive three doses of Pertussis-containing vaccine (with 28 days interval starting at two months of age).
Biological: Vaxelis® (Pertussis-containing vaccine)
Triaxis® (Pertussis-containing vaccine) will be administered: * in non-pregnant women presenting to the Travel and Vaccine clinic for pertussis immunization only or hospital member staff requiring Tetanus Toxoid (TT)-booster immunisation * in Pregnant women between 16 and 29 weeks of gestation.
Vaxelis® (Hexavalent vaccine) will be proposed in infants at 8, 12 and 16 weeks of life.
IgG titers specific to Bordetella Pertussis Antigens by Enzyme-linked immunosorbent assay (ELISA)
IgG titers specific to Bordetella Pertussis Antigens will be assessed by ELISA: * in women (pregnant and non-pregnant) at 28 days post vaccination * in infants (from unvaccinated mothers and mothers vaccinated during pregnancy) at 28 days post third vaccine dose
Time frame: Day 28 post-vaccination
IgG titers specific to Bordetella Pertussis Antigens by Enzyme-linked immunosorbent assay (ELISA)
IgG titers specific to Bordetella Pertussis Antigens will be assessed by ELISA: * in women vaccinated during pregnancy, at delivery * in umbilical cord blood of infants born to mothers vaccinated during pregnancy
Time frame: At delivery
IgG titers specific to Bordetella Pertussis Antigens by Enzyme-linked immunosorbent assay (ELISA)
IgG titers specific to Bordetella Pertussis Antigens will be assessed by ELISA: * in pregnant women (PW): at day of vaccination , day 7 post-vaccination, week 6 and 12 post-delivery * in non-pregnant women (non PW): at day of vaccination, day 7 and Month 5 post-vaccination * in infants (from unvaccinated mothers and mothers vaccinated during pregnancy) at day of first and third vaccine dose
Time frame: up to 9 month after vaccination
CD4+ T cell frequencies specific to Bordetella Pertussis Antigens by flow cytometry
The percentage of CD4+ T cells expressing any of the following biomarkers (CD154, Interferon gamma, IL-2) in response to in vitro stimulation with Bordetella Pertussis Antigens will be measured by flow cytometry: i. in pregnant and non-pregnant women: at day of vaccination, and day 28 post vaccination ii. in infants (from unvaccinated mothers and mothers vaccinated during pregnancy) at day of first vaccine dose and 28 days after third vaccine dose
Time frame: up to 9 month after vaccination
Plan to share: Yes
Supporting information: Study protocol, Icf
This study is completed, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Centre Hospitalier Universitaire Saint Pierre