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Can the DTaP vaccine cause seizures?

Here is what the checked sources say. Each title links to the original.

  1. Risk of febrile seizures and epilepsy after vaccination with diphtheria, tetanus, acellular pertussis, inactivated poliovirus, and Haemophilus influenzae type B

    JAMA, 2012, study

    This Danish study of 378,834 children found a small increase in fever- related (febrile) seizures on the day of the first two doses of a DTaP combination vaccine given at 3 and 5 months. The observed rate that day was 5.5 and 5.7 per 100,000 person-days, with hazard ratios of 6.0 and 3.9 versus children not recently vaccinated. Across the whole 0-to-7-day window no overall increase was detected, and none on the day of the third dose. Vaccination was not linked to more epilepsy; vaccinated babies had a lower epilepsy rate at 3 to 15 months, an association only.

  2. Lack of association between acellular pertussis vaccine and seizures in early childhood

    Pediatrics, 2010, study

    Using records from 7 US health systems from 1997 to 2006, researchers studied 433,654 children aged 6 weeks to 23 months and 7,191 seizure events (febrile or not, seen in hospital or emergency departments). Comparing the 4 days after each DTaP dose with other times, they found no increased risk of seizures (adjusted rate ratios 0.87 and 0.91 in two analyses). The authors called it reassuring evidence on DTaP safety with respect to seizures.

  3. Diphtheria, Tetanus and Pertussis: The Diseases & Vaccines

    Children's Hospital of Philadelphia Vaccine Education Center, 2025, explainer

    CHOP says the whole-cell DTP vaccine, used in the US before 1996, caused febrile seizures in about 1 of every 1,750 doses, and severe reactions such as very high fever, inconsolable crying or a floppy, unresponsive episode in about 1 of every 100. With today's acellular DTaP, CHOP says such severe reactions, including fever-associated seizures, occur in about 1 of every 10,000 doses. A cited Canadian study found hospital admissions for vaccine-related febrile seizures fell 79% after the switch. CHOP says a court re-examination of the main study behind fears of permanent brain damage could not support its risk figure.

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