Pneumonia; Atrial Fibrillation; Heart damage; High Blood Pressure; Chills; Body aches; Fever; Very sick; Breathing difficult; This spontaneous case was reported by a patient family member or friend and describes the occurrence of PNEUMONIA (Pneumonia), ATRIAL FIBRILLATION (Atrial Fibrillation), HEART INJURY (Heart damage), DYSPNOEA (Breathing difficult), HYPERTENSION (High Blood Pressure), ILLNESS (Very sick), CHILLS (Chills), MYALGIA (Body aches) and PYREXIA (Fever) in a 59-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 025B21A) for COVID-19 vaccination.     The patient's past medical history included No adverse event (No reported medical history).    On 02-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 05-Apr-2021, the patient experienced DYSPNOEA (Breathing difficult) (seriousness criterion hospitalization prolonged) and ILLNESS (Very sick) (seriousness criterion hospitalization). On 09-Apr-2021, the patient experienced PNEUMONIA (Pneumonia) (seriousness criterion hospitalization), ATRIAL FIBRILLATION (Atrial Fibrillation) (seriousness criterion hospitalization), HEART INJURY (Heart damage) (seriousness criterion hospitalization), HYPERTENSION (High Blood Pressure) (seriousness criterion hospitalization), CHILLS (Chills) (seriousness criterion hospitalization), MYALGIA (Body aches) (seriousness criterion hospitalization) and PYREXIA (Fever) (seriousness criterion hospitalization). The patient was hospitalized on 09-Apr-2021 due to ATRIAL FIBRILLATION, CHILLS, DYSPNOEA, HEART INJURY, HYPERTENSION, ILLNESS, MYALGIA, PNEUMONIA and PYREXIA. At the time of the report, PNEUMONIA (Pneumonia), ATRIAL FIBRILLATION (Atrial Fibrillation), HEART INJURY (Heart damage), DYSPNOEA (Breathing difficult), HYPERTENSION (High Blood Pressure), ILLNESS (Very sick), CHILLS (Chills), MYALGIA (Body aches) and PYREXIA (Fever) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In April 2021, Chest X-ray: Inconclusive. In April 2021, Echocardiogram: Inconclusive. In April 2021, Ejection fraction: 35 percent. In April 2021, Electrocardiogram: Inconclusive. In April 2021, Heart rate: (High) increased. In April 2021, Laboratory test: (Negative) tested for viruses, Covid-19 and other Infectious diseases all came back negative. In April 2021, Magnetic resonance imaging: Inconclusive. In April 2021, SARS-CoV-2 test negative: (Negative) Negative. In April 2021, Viral test: (Negative) Negative.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.       The patient was fine until 05-Apr-2021 and felt very sick, with trouble breathing, body aches, fever, chills, pneumonia and heart damage. He went into atrial fibrillation, high blood pressure, high heart rate, and an ejection fraction of 35%. He had an EKG, echocardiogram, MRI, and chest x-ray. He was tested for viruses, COVID-19 and other Infectious diseases all came back negative. He went to the emergency room on 09-Apr-2021 and was admitted to the hospital for 6 days. Concomitant product use was not provided by the reporter. Treatment information was not provided. Very limited information has been provided at this time. Further information has been requested. Based on the current information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded   This case was linked to US-MODERNATX, INC.-MOD-2021-081630, US-MODERNATX, INC.-MOD-2021-081642 (Patient Link).; Sender's Comments: Very limited information has been provided at this time. Further information has been requested. Based on the current information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded