received an extra dose of ADACEL, with no reported adverse event; patient who is pregnant received a  dose of 0.5 ml of suspect Diphtheria-2/Tetanus/5 AC Pertussis vaccine , with no reported adverse event; Initial information received on 29-Mar-2022 regarding an unsolicited valid  non-serious case received from a consumer/non-healthcare professional.  This case involves a 28 years old female patient who is pregnant received a  dose of 0.5 ml of suspect Diphtheria-2/Tetanus/5 AC Pertussis vaccine , with no reported adverse event  and received an extra dose of ADACEL, with no reported adverse event, while receiving vaccine DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE [ADACEL].  Data regarding this pregnancy were received prospectively, i.e. before pregnancy outcome was known. The reported patient who is pregnant received an extra dose of ADACEL, with no reported adverse event occurred at 28 weeks of pregnancy and received an extra dose of ADACEL, with no reported adverse event occurred at 29 weeks of pregnancy and the patient was exposed to DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE at 28 weeks of pregnancy, during third pregnancy trimester for DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE. The date of last menstrual period was reported as 05-Sep-2021. The estimated due date is 12-Jun-2022. The patient's past medical history, medical treatment(s), vaccination(s) and family history were not provided. The patient had unknown previous pregnancy/ies.  The patient's past medical history, medical treatment(s), vaccination(s) and family history were not provided.   On 17-Mar-2022, the patient who is pregnant received a  dose of 0.5 ml of suspect Diphtheria-2/Tetanus/5 AC Pertussis vaccine  (exposure during pregnancy) (latency: same day)  (lot U7271AA : expiry date: 22-NOV-2024) via intramuscular route in the left deltoid for immunization. On 28-Mar-2022 she also received a extra dose of the same vaccine (extra dose administered) (latency: 11 days) via intramuscular route in the left deltoid .  On 28-MAR-2022 the patient developed a non-serious patient who is 29 weeks and 2 days pregnant received an extra dose of adacel, with no reported adverse event (exposure during pregnancy) and non-serious patient who is 29 weeks and 2 days pregnant received an extra dose of adacel, with no reported adverse event (extra dose administered) 11 days following the administration of diphtheria-2/tetanus/5 AC pertussis vaccine.  It was reported "  patient who is 29 weeks and 2 days pregnant received an extra dose of ADACEL. Caller reporting patient received first dose on 17-Mar-2022 and inadvertently received a second dose on 28-Mar-2022."  Action taken with DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE (ADACEL) was not applicable.  It was not reported if the patient received a corrective treatment for the events (patient who is pregnant received a  dose of 0.5 ml of suspect Diphtheria-2/Tetanus/5 AC Pertussis vaccine , with no reported adverse event, received an extra dose of ADACEL, with no reported adverse event).  At time of reporting, the outcome was Unknown for the event patient who is pregnant received a  dose of 0.5 ml of suspect diphtheria-2/tetanus/5 ac pertussis vaccine , with no reported adverse event and was Unknown for the event received an extra dose of adacel, with no reported adverse event. Additionally, at time of reporting, the pregnancy is still ongoing.  This suspected adverse reaction report is submitted and classified as a medication error solely and exclusively to ensure the marketing authorization holder's compliance with the requirements set out in the Directive 2001/83/EC and Module VI of the Good Pharmacovigilance Practices. The classification as a medical error is in no way intended, nor should it be interpreted or construed as an allegation or claim made by the marketing authorization holder that any third party has contributed to or is to be held liable for the occurrence of this medication error.