This spontaneous case was reported by a consumer and describes the occurrence of ATRIAL FIBRILLATION (AFib (atrial fibrillation)), INTRACRANIAL ANEURYSM (Two aneurysms in my brain), FALL (Slipped off the bed), PERIPHERAL SWELLING (swelled up - arms and legs), OEDEMA (edema) and ILLNESS (Violently sick) in a 77-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 014M20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below. The patient's past medical history included Fibromyalgia in 1998 and Arthritis (comes and goes) in 1998. Concurrent medical conditions included Allergy, Drug allergy and Drug allergy. Concomitant products included Metoprolol Tartrate; Flecainide; Eliquis; Lisinopril; Amlodipine; Fluoxetine; Ipratropium; Albuterol [Salbutamol]; Oxygen 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 02-Apr-2021, the patient experienced FEELING ABNORMAL (feeling bad/feeling so bad). In April 2021, the patient experienced ILLNESS (Violently sick) (seriousness criterion hospitalization), DECREASED APPETITE (Wasn't hungry), LETHARGY (lethargic) and COUGH (cough). On 19-Apr-2021, the patient experienced FALL (Slipped off the bed) (seriousness criterion hospitalization). In 2021, the patient experienced ATRIAL FIBRILLATION (AFib (atrial fibrillation)) (seriousness criteria hospitalization and medically significant), INTRACRANIAL ANEURYSM (Two aneurysms in my brain) (seriousness criteria hospitalization and medically significant) and PERIPHERAL SWELLING (swelled up - arms and legs) (seriousness criterion hospitalization). On an unknown date, the patient experienced OEDEMA (edema) (seriousness criterion hospitalization), GAIT DISTURBANCE (couldn't walk), AMNESIA (memory is not what it used to be/a lot of the short term memory is gone) and ASTHENIA (No stamina. She is still very weak). The patient was hospitalized from 19-Apr-2021 to 27-Aug-2021 due to ATRIAL FIBRILLATION, FALL, ILLNESS, INTRACRANIAL ANEURYSM, OEDEMA and PERIPHERAL SWELLING. The patient was treated with IBUPROFEN for Adverse event, at a dose of 2 dosage form once a day and Physical therapy for Gait disturbance. At the time of the report, ATRIAL FIBRILLATION (AFib (atrial fibrillation)), AMNESIA (memory is not what it used to be/a lot of the short term memory is gone) and ASTHENIA (No stamina. She is still very weak) had not resolved, INTRACRANIAL ANEURYSM (Two aneurysms in my brain), FALL (Slipped off the bed), PERIPHERAL SWELLING (swelled up - arms and legs), OEDEMA (edema), FEELING ABNORMAL (feeling bad/feeling so bad), DECREASED APPETITE (Wasn't hungry), LETHARGY (lethargic), COUGH (cough) and GAIT DISTURBANCE (couldn't walk) outcome was unknown and ILLNESS (Violently sick) had resolved with sequelae. DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, SARS-CoV-2 test: negative (Negative) Negative every other day. On an unknown date, Weight: 286 pounds and 343 pounds. For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments. No Other vaccines given within 1 month prior to Moderna COVID-19 vaccine. Patient was violently sick and admitted in Hospital on 19Apr2021. Patient had not experienced a similar event in the past. AE Outcome was residual effects. Company comment: This spontaneous case concerns a 77-year old, female patient with no relevant medical history reported, who experienced the unexpected serious (hospitalization/medically significant) events of Atrial fibrillation (AESI) and Intracranial aneurysm, along with (hospitalization) events of Fall, Peripheral swelling, Oedema and Illness which occurred after receiving second dose of mRNA-1273 vaccine. Next day after vaccine she was feeling abnormal, with decreased appetite, cough and lethargy. Symptoms were persistent, approximately 19 days later she slipped off the bed and had a fall. While on the way to hospital she flatlined twice and was intubated. She had another episode of Flatline. Covid test done every day was negative. She was edematous with peripheral swelling and there was an increase in the weight from 286 pounds to 343 pounds. All tests done were normal except for Atrial fibrillation and two aneurysms in brain. She was hospitalized and under Rehabilitation for nearly 4 months. She still continues to be weak with difficulty to walk, in Atrial fibrillation and short-term memory loss. Outcome of events Intracranial aneurysm, Fall, Peripheral swelling and Oedema is not known. She has recovered from Illness with sequel. She had received 1st dose of mRNA-1273 vaccine 28 days prior to second dose. Elderly age of the patient remains a confounder to the events Atrial fibrillation, Intracranial aneurysm and Illness. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Sender's Comments: This spontaneous case concerns a 77-year old, female patient with no relevant medical history reported, who experienced the unexpected serious (hospitalization/medically significant) events of Atrial fibrillation (AESI) and Intracranial aneurysm, along with (hospitalization) events of Fall, Peripheral swelling, Oedema and Illness which occurred after receiving second dose of mRNA-1273 vaccine. Next day after vaccine she was feeling abnormal, with decreased appetite, cough and lethargy. Symptoms were persistent, approximately 19 days later she slipped off the bed and had a fall. While on the way to hospital she flatlined twice and was intubated. She had another episode of Flatline. Covid test done every day was negative. She was edematous with peripheral swelling and there was an increase in the weight from 286 pounds to 343 pounds. All tests done were normal except for Atrial fibrillation and two aneurysms in brain. She was hospitalized and under Rehabilitation for nearly 4 months. She still continues to be weak with difficulty to walk, in Atrial fibrillation and short-term memory loss. Outcome of events Intracranial aneurysm, Fall, Peripheral swelling and Oedema is not known. She has recovered from Illness with sequel. She had received 1st dose of mRNA-1273 vaccine 28 days prior to second dose. Elderly age of the patient remains a confounder to the events Atrial fibrillation, Intracranial aneurysm and Illness. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.