had A.FIB; Had shortness of breath/could not breath; had chest pain; could not lay down flat and slept in chair for days; Pericarditis; Myocarditis; GI bleed; This spontaneous case was reported by a consumer and describes the occurrence of GASTROINTESTINAL HAEMORRHAGE (GI bleed), ATRIAL FIBRILLATION (had A.FIB), PERICARDITIS (Pericarditis) and MYOCARDITIS (Myocarditis) in a 54-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 039K20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.    On 30-Dec-2020, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 03-Jan-2021, the patient experienced ATRIAL FIBRILLATION (had A.FIB) (seriousness criterion medically significant), DYSPNOEA (Had shortness of breath/could not breath), CHEST PAIN (had chest pain) and ASTHENIA (could not lay down flat and slept in chair for days). In 2021, the patient experienced GASTROINTESTINAL HAEMORRHAGE (GI bleed) (seriousness criterion medically significant), PERICARDITIS (Pericarditis) (seriousness criterion medically significant) and MYOCARDITIS (Myocarditis) (seriousness criterion medically significant). At the time of the report, GASTROINTESTINAL HAEMORRHAGE (GI bleed) outcome was unknown and ATRIAL FIBRILLATION (had A.FIB), PERICARDITIS (Pericarditis), MYOCARDITIS (Myocarditis), DYSPNOEA (Had shortness of breath/could not breath), CHEST PAIN (had chest pain) and ASTHENIA (could not lay down flat and slept in chair for days) had not resolved.        mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosing remained unchanged.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   Patient was taking regular medicines which were not specified.  Treatment included steroids which is a old anti-inflammatory. Patient developed GI bleed which patient stated that was due to anti-inflammatory. The patient had shortness of breath, A.FIB, chest pain, could not breath, could not lay down flat and slept in chair for days. The patient went to ER and they gave him steroids and it subside. GI bleed occurred from the medicine given which is old anti-inflammatory. Caller was not able to recall the name of medicine. On 28Jan2021 after patient's 2nd dose same things happened. The patient had myocarditis and pericarditis.   The patient have myocarditis and pericarditis.  Company Comment - This case concerns a 54-year-old, male patient with no medical history reported, who experienced the unexpected events of atrial fibrillation, dyspnoea, chest pain, nocturnal dyspnoea and gastrointestinal pain and expected events of myocarditis and pericarditis. The events occurred approximately 4 days after the first dose of mRNA-1273. The patient had shortness of breath, A.FIB, chest pain, could not breath, could not lay down flat and slept in chair for days. The patient went to ER and they gave him steroids which helped his symptoms subside. Patient developed GI bleed which patient attributed to the anti-inflammatory (steoids) that was given to him. The patient had same events after dose 2 and was diagnosed with myocarditis and pericarditis. The rechallenge was not applicable as patient received treatment for his symptoms. The benefit-risk relationship of mRNA-1273 is not affected by this report.   This case was linked to MOD-2021-384450 (Patient Link).; Sender's Comments: This case concerns a 54-year-old, male patient with no medical history reported, who experienced the unexpected events of atrial fibrillation, dyspnoea, chest pain, nocturnal dyspnoea and gastrointestinal pain and expected events of myocarditis and pericarditis. The events occurred approximately 4 days after the first dose of mRNA-1273. The patient had shortness of breath, A.FIB, chest pain, could not breath, could not lay down flat and slept in chair for days. The patient went to ER and they gave him steroids which helped his symptoms subside. Patient developed GI bleed which patient attributed to the anti-inflammatory (steoids) that was given to him. The patient had same events after dose 2 and was diagnosed with myocarditis and pericarditis. The rechallenge was not applicable as patient received treatment for his symptoms. The benefit-risk relationship of mRNA-1273 is not affected by this report.