True contraindications to diphtheria, tetanus, and acellular pertussis (DTaP or Tdap) vaccine include:

A. Fever up to 104°F after previous DTaP vaccine: A high fever following a previous dose of DTaP may be considered a precaution rather than a true contraindication. Post-vaccination fever can occur due to the immune system’s inflammatory response to vaccine antigens. This reaction alone does not permanently prohibit future vaccination if the benefits outweigh the risks. B. Family history of seizures after DTaP vaccine: A family history of seizures is not considered a true contraindication to receiving DTaP or Tdap. Although febrile seizures can occur in young children with fever from any cause, including vaccination, genetic or familial seizure history does not significantly increase the risk of serious neurologic complications from the vaccine. C. Adolescent pregnancy: Pregnancy, particularly during adolescence, is not a contraindication to receiving the Tdap vaccine. In fact, Tdap is recommended during each pregnancy, ideally between 27 and 36 weeks of gestation, to stimulate maternal antibody production and provide passive immunity to the newborn against pertussis. D. Anaphylactic reaction with a previous dose: A history of anaphylaxis following a previous dose of DTaP or Tdap is a true contraindication to further administration of the vaccine. Anaphylaxis is a severe, IgE-mediated hypersensitivity reaction that can cause airway compromise, hypotension, and cardiovascular collapse. Repeat exposure could provoke another life-threatening reaction, hence the vaccine should not be administered again.