Massive U.S. study to see if whooping cough vaccine is safe for pregnant women and babies
NCT ID NCT06258057
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study is using electronic medical records from about 365,000 pregnant women in the U.S. to check the safety of the Adacel vaccine, which protects against tetanus, diphtheria, and whooping cough. Researchers will compare pregnancy and birth outcomes between women who got the vaccine after 27 weeks of pregnancy and those who didn't get any Tdap vaccine. The goal is to see if the vaccine is linked to any risks like preterm birth or low birth weight.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Adacel (tetanus, diphtheria, acellular pertussis vaccine with 5 pertussis components)
- What this could lead to
- If this study finds no safety concerns, it could reassure pregnant women and doctors that the Tdap5 vaccine is safe to use during pregnancy, helping protect newborns from whooping cough.
- What could go wrong
- This is an observational study using existing medical records, not a controlled trial, so it can only show links, not cause and effect. Results may be affected by differences between the groups that aren't accounted for.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Participants
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About 365,000 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Jan 2024
- Expected to finish
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Dec 2026
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
Who is studied
The study population will be comprised of 2 cohorts of pregnant individuals with pregnancy onset from 01 January 2016 through 31 December 2024. Infants born from this study population of pregnant individuals with singleton gestation pregnancies will be eligible for inclusion in this study. Eligible live born infants must be born on 01 October 2025 or prior to this date, to allow adequate follow-up time
- Ages
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15 to 49 years
- Sex
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Female participants only
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * For pregnant individuals: * Continuous enrollment, with no more than a 1-month administrative gap from 90 days prior to their last menstrual period (LMP) * Continuous enrollment for the duration of their pregnancy through delivery or termination of pregnancy (or 6 weeks postpartum for preeclampsia/eclampsia and 28 days for PPH) unless censored at death in order to capture study outcomes * At least 1 prenatal visit prior to 27 weeks of gestation during pregnancy * For offspring: * Infants delivered by pregnant individuals who meet all the inclusion criteria above * With gestational age as calculated based on date of birth recorded in the EMR Exclusion Criteria: * For pregnant individuals: * Loss of pregnancy or with delivery before 27 weeks of gestation * Vaccinated with Boostrix® (Tdap vaccine, GSK), or with an unknown brand of Tdap vaccine, or Td (tetanus, diphtheria) vaccine during pregnancy * Vaccinated with any Tdap vaccine prior to the ACIP recommended optimal timeframe of ≥ 27 0/7 weeks of gestation * Received more than one Tdap vaccine during pregnancy * Vaccinated with one or more live vaccines during pregnancy * Pregnant individuals with multiple gestation pregnancies (eg, twins, triplets) * For offspring: * Infants delivered by pregnant individuals who meet any of the exclusion criteria above
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
-
Investigational Site
Chilly-Mazarin, 91380, France
More trials for these conditions
Other studies related to the condition(s) this trial covers.
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