This spontaneous case was reported by a consumer (subsequently medically confirmed) and describes the occurrence of ATRIAL FIBRILLATION (atrial fibrillation), PULMONARY EMBOLISM (blood clots in her lungs) and THROMBOSIS (blood clots everywhere) in an 89-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No medical history was provided by the reporter.  Concomitant products included VITAMINS NOS for an unknown indication.   On 16-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 17-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 17-Feb-2021, the patient experienced INFLUENZA LIKE ILLNESS (felt like she was getting the flu), DIARRHOEA (diarrhea), BLOOD PRESSURE ABNORMAL (no blood pressure), VACCINATION SITE PAIN (arm still hurts from time to time) and FATIGUE (felt tired). On 03-Mar-2021, the patient experienced ATRIAL FIBRILLATION (atrial fibrillation) (seriousness criterion hospitalization), PULMONARY EMBOLISM (blood clots in her lungs) (seriousness criterion hospitalization) and THROMBOSIS (blood clots everywhere) (seriousness criterion hospitalization). At the time of the report, ATRIAL FIBRILLATION (atrial fibrillation), PULMONARY EMBOLISM (blood clots in her lungs), THROMBOSIS (blood clots everywhere), INFLUENZA LIKE ILLNESS (felt like she was getting the flu), BLOOD PRESSURE ABNORMAL (no blood pressure) and FATIGUE (felt tired) outcome was unknown and DIARRHOEA (diarrhea) and VACCINATION SITE PAIN (arm still hurts from time to time) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Computerised tomogram: normal (normal) haven't found anything. On an unknown date, Endoscopy: normal (normal) haven't found anything.         Treatment medication included apixaban.  Action taken with mRNA-1273 in response to the events was not Applicable.  The patient had an endoscopy and CAT scan where they haven't found anything at when she was at the clinic.  Consumer was vaccinated with first dose on 16JAN2021 (was not able to locate lot/expiration on vaccination card). She got her second dose on 17FEB2021 (was not able to locate lot/expiration on vaccination card) and she felt like she was getting the flu, felt tired and on 3MAR2021, she was rushed to the hospital because she had "no blood pressure" and presented atrial fibrillation and blood clots in her lungs and everywhere. Her arm still hurts from time to time and continues to have diarrhea. She states she is a fairly healthy person does not take any medications, only Centrum vitamins. Since then she has gone to the clinic, had an endoscopy and CAT scan where they haven't found anything. She is now on Eliquis.  Based on the current available 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 MOD-2021-101609 (Patient Link).; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.