This case was reported in a literature article and described the occurrence of seizure in a child male patient who received DTaP vaccine. On an unknown date, the patient received DTaP vaccine at an unknown dose. On an unknown date, unknown after receiving DTaP vaccine, the patient experienced seizure (serious criteria GSK medically significant). On an unknown date, the outcome of the seizure was unknown. It was unknown if the reporter considered the seizure to be related to DTaP vaccine. Additional information was provided. This case was reported in a literature and described the occurrence of seizure in a male of unspecified age who was vaccinated with unspecified DTaP vaccine (manufacturer unknown). No information on patient's medical or family history or concomitant medication or concurrent condition was provided. On an unspecified date, at the age of 7 months, the patient received unspecified DTaP vaccine (administration route and site unspecified, dosage unknown; batch number). On an unspecified date, an unknown period after vaccination, the patient had seizure. The patient's physician advised him to avoid pertussis vaccination due to seizure. On an unspecified date, at the age of 13 years, the patient presented with congestion and cough. His cough was spasmodic with post-tussive gagging. No fevers were reported. Physical examination revealed clear oropharynx, no wheezing and no other abnormalities. The patient had suffered from moderate persistent asthma and depression. The patient was on paliperidone, imipramine, and hydroxyzine prescribed by his psychiatrist. The patient had severe rash with Trimethoprim-sulphamethoxazole (TMP-SMX) and allergic reaction to amoxicillin. Subsequently, the patient's nasopharyngeal swab was positive for Bordetella pertussis by polymerase chain reaction (PCR).Both paediatric infectious disease and a PharmD were consulted. The patient's paediatrician considered referral for penicillin skin-testing and rapid desensitisation; however the need for timely treatment and concern for exposing others made that option nonviable. Doxycycline 100 mg BID for 10 days was recommend based on historical use and documented in vivo evidence of efficacy. An electrocardiogram (ECG) was obtained to evaluate QT status, considering his multiple medications, and was found that the QT was normal. A follow up nasopharyngeal culture obtained after treatment, 17 days after initial presentation and 24 days after onset of symptoms, was negative. Treatment for seizure was unknown. The patient reported improvement in symptoms of pertussis infection. The outcome of the event of seizure was unknown. A Tdap was strongly advised. The authors did not comment on causal relationship between event of seizure and unspecified DTaP vaccine. The authors stated "the pertussis has increased from 4570 cases in 1990 to 32,971 in 2014. With the increase of pertussis, treatment to shorten duration of symptoms and decrease transmission is important. Due to rise in polypharmacy, paediatricians may encounter patients unable to use standard recommended treatments. Macrolides have been effective in the treatment of pertussis, but in patients unable to take a macrolide TMP-SMX is recommended. This case illustrated another alternative when these first two lines cannot be used: doxycycline. This case also reminds physicians of recognizing potential drug-drug interactions such as prolonged QT syndrome".