Pregnant women who post about the maternal Tdap vaccine on Reddit are mostly looking for advice and reassurance rather than arguments against vaccination, according to a qualitative analysis published this month in PLOS Global Public Health by researchers at Purdue University.
The study summary reports that the research, led by Soojung Jo, documented fewer outright instances of hesitancy or refusal than have generally been observed in social media discussions of other vaccines. The most common pattern was a woman trying to resolve a specific question her clinician had not fully answered.
For expectant parents, that finding reframes a familiar assumption. The dominant online conversation about maternal Tdap is not a debate. It is a queue of unresolved questions, and most of them have straightforward clinical answers.
The Study Measured a Narrow Slice of Conversation
Researchers searched English-language Reddit posts from October 2020 through October 2023 for the terms Tdap, pertussis, whooping cough, and pregnant, identifying 173 relevant posts. They then applied three inclusion criteria: the post had to be written from the perspective of a pregnant woman, created before delivery, and have maternal Tdap vaccination as its primary concern. That left 86 posts for analysis.
Eighty-six posts are a small sample, and it is a qualitative one by design. The design was built to characterize the kinds of questions people ask, not to estimate how common any view is among American mothers. Reddit users are not representative of pregnant women generally, and the study period ended in 2023.
Those limits should be stated plainly, because the finding is easy to misread. The study does not establish that maternal Tdap hesitancy is rare. It establishes that within this sample of posts, clarification-seeking outnumbered refusal discussion.
The Questions Point to Real Counseling Gaps
The specific confusions the researchers documented are the most actionable part of the work. Several posters asked whether a Tdap dose received years earlier still provided antibodies during the current pregnancy. One described being told by a doctor that she did not need Tdap because she had received it shortly before becoming pregnant, then worrying that her baby would be unprotected.
That is not a hesitancy problem. It is an information problem, and it has a clear answer. The Centers for Disease Control and Prevention recommends Tdap during every pregnancy, preferably between 27 and 36 weeks of gestation, regardless of prior Tdap history. The reason is timing rather than immunity, generally. Antibodies generated by maternal vaccination cross the placenta and reach peak transfer in the weeks after the dose, which is what protects a newborn during the window before the infant's own vaccine series begins.
Some posters sought reassurance about vaccine safety or about their right to decline. In an account summarized by CIDRAP News, the authors noted that discussions of hesitancy or negativity toward Tdap were less common than in social media conversations about other vaccines.
Coverage Rates Remain the Larger Problem
The study's framing is supported by the underlying numbers. Roughly 55 percent of eligible pregnant women in the United States received the maternal Tdap vaccine in 2023, meaning close to half did not.
That gap has consequences for infants. Babies under two months are too young to be vaccinated against pertussis and rely on maternal antibodies and the immunity of those around them. Infants under 12 months account for nearly all pertussis deaths in the United States. Nationally, pertussis case counts are running well below last year's pace, but the scale of recent seasons is the relevant backdrop: a vaccination coverage analysis from Johns Hopkins noted nearly 29,000 cases and 16 related deaths in 2025, the highest case count since 2012. MedicalDaily previously reported that two children have died from whooping cough in surveillance data reported so far this year.
If the Purdue findings reflect a broader pattern, then a meaningful share of the coverage gap may be driven by unresolved practical questions rather than opposition. The CDC's guidance on vaccines during pregnancy addresses most of the specific scenarios raised in the posts, including questions about prior doses, timing, and intervals.
Practical Steps for Expectant Parents
The most useful action is to ask a specific question rather than a general one. Whether a previous Tdap dose counts, whether the timing window has been missed, and whether a partner or grandparent needs a booster are all answerable in a single appointment.
Tdap during pregnancy is covered without cost-sharing by most private insurance plans under preventive care rules, and is available through obstetric offices, many pharmacies, and county health departments. Patients who encounter a coverage problem can ask their obstetric office to bill it as a pregnancy-related preventive service.
Household contacts matter too. Adults with waning immunity are a common source of infant pertussis exposure, and an adult's persistent cough is easy to dismiss as a seasonal illness. Anyone who will spend time with a newborn should confirm they have had a Tdap booster at least two weeks before contact. The study authors themselves recommended that public health campaigns target close contacts as well as pregnant women, so that the burden of persuading family members does not fall on the mother.
Parents should call a pediatrician promptly if an infant under 12 months develops a cough accompanied by any pause in breathing, difficulty feeding, exhaustion after coughing spells, or a bluish color around the lips. An infant who stops breathing, even briefly, needs emergency evaluation rather than a same-day appointment. In infants, pertussis often presents without the characteristic whooping sound, and pauses in breathing are common among those sick enough to be hospitalized. MedicalDaily has also reported on how adults spread pertussis to newborns unknowingly without realizing it.
None of this is a substitute for a conversation with an obstetric clinician, and the study does not evaluate vaccine safety or effectiveness. It evaluates what people are asking. The researchers suggest that clinicians and public health communicators could use these documented question patterns to design better counseling materials, a modest recommendation well supported by the study's findings.
Key Questions Answered
What did the study analyze? Eighty-six Reddit posts written by pregnant women about the maternal Tdap vaccine, drawn from 173 relevant posts identified between October 2020 and October 2023.
What was the main finding? Most posters sought information, clarification, or reassurance. The researchers documented fewer instances of outright hesitancy or refusal than have generally been observed for other vaccines.
Does this mean Tdap hesitancy is rare? No. This was a small qualitative study of a self-selected online population. It describes the kinds of questions asked, not how common any view is among American mothers.
When should pregnant women get Tdap? CDC recommends a dose during every pregnancy, preferably between 27 and 36 weeks, regardless of prior Tdap history.
Why does a previous dose not count? Protection for the newborn depends on antibody transfer across the placenta, which peaks in the weeks after vaccination, so each pregnancy requires a new dose.
How many pregnant women get vaccinated? About 55 percent of eligible pregnant women in the United States received the maternal Tdap vaccine in 2023.
What should household members do? Adults who will be around a newborn should confirm they have had a Tdap booster, ideally at least two weeks before contact with the infant.
