diagnosed with miocarditis; low grade fever; shortness of breath; chest pain/ mid-sternal pain; chills; 29 weeks pregnant patient received a vaccination of Adacel; Initial information was received on 02-Jul-2020 regarding an unsolicited valid serious case from a other health professional.  This case involves a 30 year old female pregnant patient who was diagnosed with myocarditis (myocarditis)  with the symptoms of low grade fever (pyrexia), shortness of breath (dyspnoea), chest pain/ mid-sternal pain (chest pain), chills and (exposure during pregnancy) while she received DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE [ADACEL].   Data regarding this pregnancy were received prospectively, i.e. before pregnancy outcome was known.   The patient was 29 Weeks pregnant at the time of reporting the adverse event. The date of last menstrual period was not reported. The estimated due date was not reported. The data regarding previous pregnancy was not reported. The patient did not received any other medications or vaccines at that visit.  The patient denied having any reactions to previous vaccines or serious illness.  On 26-Jun-2020, the patient received a 0.5 ml dose of suspect DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE (lot U66288A and expiration date: 04-Apr-2022) via intramuscular route in the left deltoid as prophylactic vaccination.  On an unknown date , the patient was diagnosed with myocarditis (myocarditis)  with the symptoms of low grade fever (pyrexia), shortness of breath (dyspnoea), chest pain/ mid-sternal pain (chest pain), chills, within 24 hours (exact latency unknown) following the administration of DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE. These events were assessed as medically significant. The patient was hospitalized for these events. The patient was hospitalized on an unknown date and was discharged on 30-Jun-2020 with a holter monitor.  This was also a case of vaccine exposure during pregnancy.  Relevant laboratory test results included: On an unknown dates below laboratory tests were performed:  Computerised tomogram - diagnosed with myocarditis Echocardiogram - diagnosed with myocarditis Electrocardiogram - diagnosed with myocarditis  Laboratory test - low troponin Ultrasound scan - results not reported Her labwork showed low troponin.  Final diagnosis was myocarditis (myocarditis) with the symptoms of low grade fever (pyrexia), shortness of breath (dyspnoea), chest pain/ mid-sternal pain (chest pain) and chills.  It was not reported if the patient received a corrective treatment.  At the time of reporting, the outcomes were unknown for all the events except for the event dyspnea was not recovered.  Additionally, at time of reporting, the outcome of the pregnancy was unknown.; Sender's Comments: This case concerns 30 years old female pregnant patient who was diagnosed with myocarditis with the symptoms of lowgrade fever, shortness of breath, chest pain, chills, within 24 hours after vaccination with ADACEL.The patient received the ADACEL while she was pregnant. The time to onset is compatible. However, patient's medical condition at the time of vaccination and lab tests ruling out other etiologies were not reported. Based upon the reported information, the role of the vaccine cannot be assessed.