This spontaneous case was reported by a consumer and describes the occurrence of CARDIAC FLUTTER (Patient ends up in the hospital with heart flutter) and HYPERCOAGULATION (Patient reports his blood is getting thick) in a 74-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. C08C21A and D17B21A) for COVID-19 vaccination.     Concurrent medical conditions included Blood pressure high (Patient has a past medical history of high blood pressure taking hydrochlorothiazide and 5mg of lisinopril.). Concomitant products included HYDROCHLOROTHIAZIDE and LISINOPRIL for Blood pressure high.   On 24-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 22-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 08-Jun-2021, the patient experienced CARDIAC FLUTTER (Patient ends up in the hospital with heart flutter) (seriousness criteria hospitalization and medically significant). On an unknown date, the patient experienced HYPERCOAGULATION (Patient reports his blood is getting thick) (seriousness criterion hospitalization). The patient was hospitalized from 08-Jun-2021 to sometime in June 2021 due to CARDIAC FLUTTER. The patient was treated with APIXABAN (ELIQUIS) for Hypercoagulability, at an unspecified dose and frequency and Immobilization for Cardiac flutter. At the time of the report, CARDIAC FLUTTER (Patient ends up in the hospital with heart flutter) and HYPERCOAGULATION (Patient reports his blood is getting thick) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Platelet count: 19 (High) Patient states last week his platelets were 19 and they are supposed to be 12. On an unknown date, SARS-CoV-2 test: negative (Negative) Patient reports not having tested positive for covid19.         The patients heart was shocked for cardiac flutter.  For blood thickening the patient is using blood thinners from when he was in hospital. The Patient reports he had ended up in the hospital three times since the shot. Patient states last week he was told by his doctor that he will have to get blood drawn monthly because his platelets were 19 and they are supposed to be 12. Patient is on Eliquis which is $138 a month that he must spend. Patient states he is not getting better. Company Comment This case concerns a 74-year-old, male patient with relevant medical history of hypertension, who experienced the unexpected events of cardiac flutter and hypercoagulation. The events occurred 2 months and 16 days after the second dose of mRNA-1273. The rechallenge was not applicable since the events happened after the second dose. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This case concerns a 74-year-old, male patient with relevant medical history of hypertension, who experienced the unexpected events of cardiac flutter and hypercoagulation. The events occurred 2 months and 16 days after the second dose of mRNA-1273. The rechallenge was not applicable since the events happened after the second dose. The benefit-risk relationship of mRNA-1273 is not affected by this report