hypertensive crisis; running a fever for the past four weeks (temperature > 100); headache/felt like her head would explode; nausea; gained 20 lbs.; This spontaneous case was reported by a nurse and describes the occurrence of HYPERTENSIVE CRISIS (hypertensive crisis) in a 65-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 018B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Atrial fibrillation, Arrhythmia, Cardiomyopathy, Heart failure, Lymphoma (2-3 years ago), Clot blood in 2018, Cardiac resynchronization therapy in 2018, Defibrillator/pacemaker insertion in 2018 and Cardiac catheterisation in 2018. Concomitant products included PROPAFENONE (RYTHMOL), ALUMINIUM HYDROXIDE GEL, DRIED, MAGNESIUM CARBONATE (PEPCID), LEVOTHYROXINE SODIUM (SYNTHROID), APIXABAN (ELIQUIS), BUMETANIDE (BUMEX), POTASSIUM and MAGNESIUM for an unknown indication.    On 10-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 10-Apr-2021, the patient experienced WEIGHT INCREASED (gained 20 lbs.). On 18-May-2021, the patient experienced HYPERTENSIVE CRISIS (hypertensive crisis) (seriousness criteria hospitalization and medically significant). On 30-Jun-2021, the patient experienced HEADACHE (headache/felt like her head would explode) and NAUSEA (nausea). On an unknown date, the patient experienced BODY TEMPERATURE INCREASED (running a fever for the past four weeks (temperature > 100)). The patient was treated with ATENOLOL (TENORMIN) ongoing since an unknown date at a dose of 200 mg; LORAZEPAM (ATIVAN) ongoing since an unknown date at a dose of 1 mg every other day; SPIRONOLACTONE at a dose of 25 mg twice a day and AMLODIPINE at a dose of 5 mg twice a day. At the time of the report, HYPERTENSIVE CRISIS (hypertensive crisis), BODY TEMPERATURE INCREASED (running a fever for the past four weeks (temperature > 100)), WEIGHT INCREASED (gained 20 lbs.), HEADACHE (headache/felt like her head would explode) and NAUSEA (nausea) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 30-Jun-2021, Blood electrolytes decreased: low (Low) Low. On 30-Jun-2021, Blood pressure fluctuation: 254/140 (High) 254/140. On 30-Jun-2021, Inflammatory marker increased: high (High) High. On 30-Jun-2021, Monocyte count increased: high (High) High. On an unknown date, Blood pressure fluctuation: 290/145 290/145.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   The patient had been running a fever for the past four weeks. The patient electrolytes was below normal, her monocytes was high, and inflammation markers was all high. The patient had been hospitalized four or five times since 10/Apr/2021. The patient had to go to the Emergency Room yesterday (30Jun2021) as her blood pressure elevated to 254/140. In addition the patient was experiencing a headache, and nausea and reported that it felt like her head would explode.  Company Comment: 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-2021-244633 (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.