This spontaneous case was reported by a consumer and describes the occurrence of BLOOD PRESSURE FLUCTUATION (BP stayed high and fluctuated between 150-160/100-110), ERYTHEMA (red circle), HEADACHE (Severe headache on side of head), MYALGIA (body ache/soreness) and FATIGUE (Fatigue) in a 39-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 939905, 0251202A and 042L20A) for COVID-19 vaccination. Previously administered products included for Product used for unknown indication: Influenza (Route: Intramuscular Body site/side: Left bicep). Past adverse reactions to the above products included No adverse event with Influenza. Concurrent medical conditions included Blood pressure high (controlled for 12 years) since 2009, Klippel-Feil syndrome, Chronic back pain, Sulfonamide allergy (Hives), Drug allergy (Hives) since 2004, Asthma, Depression since 2003, Anxiety since 2003 and Pain. Concomitant products included BUSPIRONE for Anxiety, PAROXETINE for Depression, LISINOPRIL for Hypertension, AMITRIPTYLINE and MELOXICAM (MELOXICAM A) for Pain, GALCANEZUMAB (EMGALITY [GALCANEZUMAB]) for an unknown indication. On 29-Dec-2020, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 28-Jan-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 12-Nov-2021 at 1:00 PM, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 13-Nov-2021, the patient experienced MYALGIA (body ache/soreness). On 14-Nov-2021 at 10:00 AM, the patient experienced HEADACHE (Severe headache on side of head). On 15-Nov-2021, the patient experienced BLOOD PRESSURE FLUCTUATION (BP stayed high and fluctuated between 150-160/100-110). On an unknown date, the patient experienced ERYTHEMA (red circle) and FATIGUE (Fatigue). The patient was treated with METOPROLOL ongoing from 23-Nov-2021 for Adverse event, at a dose of 100 mg. At the time of the report, BLOOD PRESSURE FLUCTUATION (BP stayed high and fluctuated between 150-160/100-110), ERYTHEMA (red circle), MYALGIA (body ache/soreness) and FATIGUE (Fatigue) outcome was unknown and HEADACHE (Severe headache on side of head) had not resolved. DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 15-Nov-2021, Blood pressure measurement: 160/100 (High) 160/100 mmHg at 8:00. On 17-Nov-2021, Blood pressure measurement: 160/90 (High) 160/90 mmHg at 8:00. On 22-Nov-2021, Blood pressure measurement: 196/120 (High) 196/120, 150/90 (High) 150/90, 190/120 (High) 190/120 mmHg at 8:00 and 178/98 (High) 178/98 mmHg at 13:00. On 22-Nov-2021, Computerised tomogram head: normal (normal) normal. On an unknown date, Blood pressure measurement: 167/90 (High) 167/90. For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered HEADACHE (Severe headache on side of head) to be possibly related. No further causality assessments were provided for BLOOD PRESSURE FLUCTUATION (BP stayed high and fluctuated between 150-160/100-110), ERYTHEMA (red circle), MYALGIA (body ache/soreness) and FATIGUE (Fatigue). At the emergency room, patient received another blood pressure pill and it got down to 150/90. On 22-Nov-2021, patient received booster dose and later that night patient had body aches and headache. On 14-Nov-2021, patient stated having severe headaches, it was 160/100 and felt fatigued, tried to relax. Headache continued next day with BP of 160/90. Still felt fatigue till week and headache was continued.  On 22-Nov-2021, patient woke up with worst headache and blood pressure of 190/120, went to emergency room. At emergency room, patient was treated with unspecified BP medication via oral route and head CT was negative. Treatment medication brought BP down to 158/90 and was discharged.  On 23-Nov-2021, patient woke up with headache and BP was 180/100. Patient physician changed the treatment medication to Metoprolol 100 mg and that was keeping patient BP at 140/90. It was reported that prior to booster dose, patient had yearly physio where BP and labs were normal.This case was linked to MOD-2021-396087 (Patient Link).Most recent FOLLOW-UP information incorporated above includes:On 29-Nov-2021: Follow up added facility information, route and time of administration of third dose, patient details, medical history, concomitant medication details, treatment medication, historical vaccine, event details updated and new event was added.