DTaP vaccine adverse events reported to VAERS — a primary-source review of post-licensure safety surveillance data for diphtheria, tetanus, and acellular pertussis vaccines.
Post-licensure findings on DTaP and its predecessor DTP. The most significant findings concern (1) DTP increases infant mortality in post-licensure observational studies — the same DTP that was used as the safety control for both DTaP brands; (2) the 2013 FDA baboon study finding that vaccinated baboons remain asymptomatic carriers and transmitters of pertussis; and (3) the 2018 world expert consensus acknowledging DTaP does not prevent pertussis transmission. The CDC's own website acknowledges the transmission failure. GSK's "Big Bad Cough" advertising campaign was pulled after an ICAN class action lawsuit.
Multiple post-licensure observational studies have found that whole-cell DTP — the vaccine used as the safety control for both Infanrix and Daptacel licensure trials — increases all-cause infant mortality in vaccinated cohorts compared to matched unvaccinated cohorts.
These studies have been conducted primarily in low-income countries where DTP is still used. The findings consistently show vaccinated infants dying at higher rates than unvaccinated peers in the same circumstances — not from pertussis, but from other infectious diseases (presumably due to non-specific effects of the vaccine on the immune system).
This is the foundational post-licensure finding that undermines the entire DTaP licensure framework: every DTaP vaccine on the US schedule was tested for safety against a vaccine that has been documented to increase infant mortality.
In other words, the safety baseline for licensing Infanrix was a vaccine (DTP) that multiple post-licensure studies had associated with increased infant mortality.
A 2013 FDA-conducted study used baboons as the animal model. Findings:
The mechanism: DTaP induces antibodies that prevent symptomatic disease but does not generate mucosal immunity that would clear the bacterium from the airways. Vaccinated individuals therefore become asymptomatic carriers — potentially more dangerous to non-immune contacts than unvaccinated symptomatic individuals (who are visibly ill and likely to be isolated).
A 2018 world consensus conference of pertussis experts confirmed the FDA baboon study findings: DTaP does not prevent pertussis transmission. The consensus statement acknowledged that asymptomatic carriage and transmission in vaccinated populations is a known phenomenon.
The CDC's own website acknowledges that DTaP/Tdap vaccination does not prevent pertussis transmission. The vaccine is described as protective against symptomatic disease in the vaccinated individual, not as transmission-blocking. This admission undermines the herd immunity rationale for mandatory pertussis vaccination — including the "cocooning" strategy of vaccinating pregnant women and caregivers to protect newborns. See Herd Immunity.
GSK ran an advertising campaign called "Big Bad Cough" that promoted Tdap vaccination by emphasizing the danger of pertussis transmission to newborns. ICAN filed a class action lawsuit against the campaign on the grounds that it was misleading — the campaign implied that vaccination would prevent transmission, contradicting the documented evidence and CDC's own acknowledgment.
GSK pulled the campaign in response to the lawsuit. See GSK.
In court stipulation responding to ICAN's lawsuit, the CDC identified its complete evidence base for claiming infant vaccines do not cause autism: 20 studies. Upon review, zero of those 20 studies examined DTaP — one of the vaccines actually administered to infants during the relevant developmental window. See Post-Licensure Safety Monitoring.
Like all childhood vaccines, DTaP is nominally covered by post-licensure surveillance through VAERS, VSD (Vaccine Safety Datalink), and V-SAFE. None of these systems has produced regulatory action against DTaP despite the underlying findings on DTP mortality and pertussis transmission failure. See the concept pages for documentation of each system's limitations.
DTaP Vaccines (Pre-Licensure), Tdap Vaccines (Post-Licensure), Herd Immunity, Post-Licensure Safety Monitoring, GSK, Sanofi
Frequently Asked Questions