Sex: M
Vaccine: FLUX
Symptoms: Myocarditis, Red blood cell sedimentation rate normal, Respiratory viral panel, Sleep disorder, Troponin I increased
Clinical narrative: Atypical acute myocarditis due to influenza vaccine/Influenza vaccine induced myocarditis; Midsternal chest pain (pain as someone sitting on chest, worsened with lying down and alleviated by leaning forward); Reduced exercise tolerance; Exertional shortness of breath; Myalgias; Fibrosis of the anteroseptal wall from mid cavity extending to apex; Initial information received on 27-Mar-2024 via health care professional regarding an unsolicited valid serious case issued from a literature conference abstract:  This case involves a 32-year-old male patient who experienced atypical acute myocarditis due to influenza vaccine/influenza vaccine induced myocarditis while receiving vaccine Influenza Vaccine (latency: 1 day).  The patient's past medical treatment(s) and vaccination(s) were not provided.  The patient had no medical history.   On an unknown date, the patient received a dose of suspect Influenza vaccine produced by unknown manufacturer lot number not reported via unknown route in unknown administration site.  On an unknown date, two days later, the patient was presented with midsternal chest pain (Chest pain). He described the pain as someone sitting on his chest, worsened with lying down and alleviated by leaning forward. The pain lasted 10 minutes and awoke him from sleep. He had reduced exercise tolerance (Exercise tolerance decreased) and exertional shortness of breath (Dyspnoea exertional) for past few days. Denied recent sick contacts, however he received the flu shot two days prior to presentation and felt myalgias (Myalgia) the day prior. Denied family history of sudden cardiac death, however his father underwent coronary artery bypass graft (CABG) in his 50s for coronary artery disease (CAD). High-sensitivity (HS)-Troponin I was elevated and peaked at 7,453 before declining. Creatine phosphokinase (CPK) and creatine kinase-myoglobin binding (CK-MB) were both elevated. Brain natriuretic peptide (BNP), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were within normal limits. Low-density lipoprotein (LDL) was elevated at 115. Viral respiratory panel was negative. Electrocardiogram (EKG) demonstrated PR depressions in leads II, III, augmented vector foot (aVF), and V4-V6 with ST segment elevations in V5 and V6. Echocardiogram showed no abnormalities. He received Aspirin 650 mg every 8 hours and Colchicine 0.6 mg twice daily. Cardiac magnetic resonance imaging (MRI) demonstrated mid myocardial enhancement and fibrosis of the anteroseptal wall from mid cavity extending to apex (Myocardial fibrosis), consistent with myocarditis. He was discharged with outpatient follow up and advised to avoid strenuous activity.   Author stated that, influenza vaccine induced myocarditis (Myocarditis) is a rare clinical scenario which should be included in the differential when young, healthy patients present with chest pain and exertional dyspnea.  Action taken: Not applicable. Corrective treatment: Aspirin and Colchicine. Outcome: Unknown. Seriousness criteria: Hospitalization and medically significant. Reporter's causality: Related.; Sender's Comments: Sanofi company comment dated 27-Mar-2024: This case involves a 32-year-old male patient who experienced atypical acute myocarditis due to influenza vaccine/influenza vaccine induced myocarditis while receiving vaccine Influenza Vaccine. Based on information received the causal role of Vaccine cannot be excluded due to compatible temporal relationship of ADR to the Vaccine. Further information regarding concurrent condition during vaccination, previous vaccination, tolerance, allergic history, laboratory investigations excluding alternative etiologies for the reported event are needed to fully assess this case. Based upon the reported information, the role of vaccine cannot be assessed.