four 2 liters of pee flushed out of body; A-fib; 25 pound water weight gain; dry cough with phlegm; feeling tired; Water blisters on leg where skin was coming off; This spontaneous case was reported by a consumer and describes the occurrence of ATRIAL FIBRILLATION (A-fib), FLUID RETENTION (25 pound water weight gain), URINE OUTPUT INCREASED (four 2 liters of pee flushed out of body) and PRODUCTIVE COUGH (dry cough with phlegm) in a 69-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 037A21B and 5A21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Blood pressure high. Concomitant products included IBUPROFEN, POTASSIUM and OMEPRAZOLE for an unknown indication.   On 04-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 01-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 25-May-2021,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced BLISTER (Water blisters on leg where skin was coming off). On 13-Jun-2021, the patient experienced PRODUCTIVE COUGH (dry cough with phlegm) (seriousness criterion hospitalization prolonged). On 23-Jun-2021, the patient experienced ATRIAL FIBRILLATION (A-fib) (seriousness criteria hospitalization prolonged and medically significant) and FLUID RETENTION (25 pound water weight gain) (seriousness criterion hospitalization prolonged). On 27-Jun-2021, the patient experienced FATIGUE (feeling tired). On an unknown date, the patient experienced URINE OUTPUT INCREASED (four 2 liters of pee flushed out of body) (seriousness criterion hospitalization prolonged). The patient was hospitalized from 23-Jun-2021 to 26-Jun-2021 due to ATRIAL FIBRILLATION, FLUID RETENTION, PRODUCTIVE COUGH and URINE OUTPUT INCREASED. The patient was treated with GUAIFENESIN (MUCINEX) for Cough, at an unspecified dose and frequency and DEXTROMETHORPHAN HYDROBROMIDE, GUAIFENESIN (MUCINEX DM) for Cough, at an unspecified dose and frequency. On 26-Jun-2021, FLUID RETENTION (25 pound water weight gain) had resolved. At the time of the report, ATRIAL FIBRILLATION (A-fib), URINE OUTPUT INCREASED (four 2 liters of pee flushed out of body) and BLISTER (Water blisters on leg where skin was coming off) outcome was unknown and PRODUCTIVE COUGH (dry cough with phlegm) and FATIGUE (feeling tired) had not resolved.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Concomitant information included blood pressure medication. Treatment information included Blood thinner (not specified) for A-fib. The patient reported four 2 liters of pee flushed out of his body where he went from 259 pounds upon admission to 226 pounds on 27June2021. The patient had an appointment with his cardia doctor for the A-fib 06july2021. Action taken with M-RNA-1273 (Moderna Covid-19 Vaccine) in response to the event was not applicable.  Company Comment : Very limited information regarding these events have been provided at this time. The long latency period and patient's history of high blood pressure may be confounding factors to the events. Further information has been requested.; Sender's Comments: Very limited information regarding these events have been provided at this time. The long latency period and patient's history of high blood pressure may be confounding factors to the events. Further information has been requested.