RIGHT CALF REDNESS AND TENDERNESS; RIGHT CALF REDNESS AND TENDERNESS; RASH-TORSO, ARMS, LEGS AND ITCHING; Blurry vision; Muscle aches/body aches; Small rash on torso after 2nd Moderna vaccine; Slight fever; This spontaneous case was reported by a patient and describes the occurrence of ERYTHEMA (RIGHT CALF REDNESS AND TENDERNESS), PAIN IN EXTREMITY (RIGHT CALF REDNESS AND TENDERNESS), RASH PRURITIC (RASH-TORSO, ARMS, LEGS AND ITCHING), VISION BLURRED (Blurry vision) and MYALGIA (Muscle aches/body aches) in a 63-year-old patient of an unknown gender who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for an unknown indication.    No Medical History information was reported.   On 25-Mar-2021 at 3:00 PM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular use) 1 dosage form. On 21-Apr-2021 at 1:00 PM, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular use) dosage was changed to 1 dosage form. On 30-Nov-2021 at 2:00 PM, the patient received third dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (Intramuscular use) 1 dosage form. On 22-Apr-2021, the patient experienced MYALGIA (Muscle aches/body aches), RASH (Small rash on torso after 2nd Moderna vaccine) and PYREXIA (Slight fever). On 01-Dec-2021, the patient experienced VISION BLURRED (Blurry vision). On 04-Dec-2021, the patient experienced RASH PRURITIC (RASH-TORSO, ARMS, LEGS AND ITCHING). On 09-Dec-2021, the patient experienced ERYTHEMA (RIGHT CALF REDNESS AND TENDERNESS) and PAIN IN EXTREMITY (RIGHT CALF REDNESS AND TENDERNESS). The patient was treated with LORATADINE (CLARITIN [LORATADINE]) for Rash, at an unspecified dose and frequency; Radiotherapy (Ultrasound) for Erythema and Radiotherapy (Ultrasound) for Pain in extremity. On 23-Apr-2021, MYALGIA (Muscle aches/body aches), RASH (Small rash on torso after 2nd Moderna vaccine) and PYREXIA (Slight fever) had resolved. On 04-Dec-2021, VISION BLURRED (Blurry vision) had resolved. On 14-Dec-2021, ERYTHEMA (RIGHT CALF REDNESS AND TENDERNESS) and PAIN IN EXTREMITY (RIGHT CALF REDNESS AND TENDERNESS) had resolved. On 30-Dec-2021, RASH PRURITIC (RASH-TORSO, ARMS, LEGS AND ITCHING) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 08-Dec-2021, Complement analysis (38.7-89.9): 52.6 U/mL. On 08-Dec-2021, Complement factor C1 (0-3.9): 3.2 microgram equivalent per milliliter. On 08-Dec-2021, Complement factor C4 (15-57 milligram per decilitre): 29 milligram per decilitre. On 10-Dec-2021, Alanine aminotransferase (0-55 U/L): 22 U/L. On 10-Dec-2021, Anion gap (7-14 millimole per litre): 8 millimole per litre. On 10-Dec-2021, Aspartate aminotransferase (5-34 U/L): 18 U/L. On 10-Dec-2021, Blood albumin (3.5-5.0 gram per decilitre): 4.0 gram per decilitre. On 10-Dec-2021, Blood alkaline phosphatase (40-150 U/L): 70 U/L. On 10-Dec-2021, Blood bilirubin (0-1.4 milligram per decilitre): 0.5 milligram per decilitre. On 10-Dec-2021, Blood calcium (8.4-10.2 milligram per decilitre): 9.5 milligram per decilitre. On 10-Dec-2021, Blood chloride (98-107 millimole per litre): 103 millimole per litre. On 10-Dec-2021, Blood creatinine (0.55-1.02 milligram per decilitre): 0.83 milligram per decilitre. On 10-Dec-2021, Blood glucose (70-99 milligram per decilitre): 84 milligram per decilitre. On 10-Dec-2021, Blood potassium (3.5-5.1 millimole per litre): 4.2 millimole per litre. On 10-Dec-2021, Blood sodium (136-145 millimole per litre): 138 millimole per litre. On 10-Dec-2021, Blood urea (7-19 milligram per decilitre): 21 milligram per decilitre. On 10-Dec-2021, Glomerular filtration rate (60-120): 75 ml/min/1.735sqm. On 10-Dec-2021, Haematocrit (34-46 %): 44 %. On 10-Dec-2021, Haemoglobin (11.6-15.6 gram per decilitre): 14.4 gram per decilitre. On 10-Dec-2021, Mean cell haemoglobin concentration (32-36 gram per decilitre): 33 gram per decilitre. On 10-Dec-2021, Mean cell volume (80-97 fL): 92 fL. On 10-Dec-2021, Platelet count (160-370): 259. On 10-Dec-2021, Protein total (6.4-8.3 gram per decilitre): 7.5 gram per decilitre. On 10-Dec-2021, Red blood cell count (3.8-5.2): 4.8m/ul. On 10-Dec-2021, Red cell distribution width (36.0-46.0 fL): 40.7 fL and 12.5 %. On 10-Dec-2021, White blood cell count (3.8-10.5): 7.5 R/ul. On 29-Dec-2021, Blood folate: 16.9 ng/mL reference: greater than or equal to 7.0 ng/ml. On 29-Dec-2021, Blood glucose (70-99): 91. On 29-Dec-2021, Blood thyroid stimulating hormone (0.35-4.94 international unit per millilitre): 1.75 international unit per millilitre. On 29-Dec-2021, Fibrin D dimer (0-0.49 microgram per millilitre): 1.18 microgram per millilitre. On 29-Dec-2021, Glycosylated haemoglobin (4.0-5.6 %): 5.8 %. On 29-Dec-2021, Vitamin B12 (213-816 pg/ml): 384 pg/ml. On 31-Dec-2021, Ultrasound Doppler: US peripheral doppler bilateral test : No blood clot in either leg. On an unknown date, Allergy test: The testing indicated no allergic reactions..         Patient was not taking any concomitant medications.  On 10-Dec-2021, the patient had undergone some comprehensive metabolic panel and CBC w/o differential tests.  Patient developed fever, muscle aches (expected) and rash (unexpected and unexplained) from the second dose vaccination of Moderna. After discussion with primary care provider, the patient was recommended to take booster dose of Pfizer vaccine and patient received it. This resulted in the patient having less fever and body aches but having several days of blurry vision and much more significant/severe longer-lasting rash along with itchiness for several weeks. The testing indicated no allergic reactions and the patient did not know whether it was safe to receive any additional COVID vaccinations or not and asked for advise.  Patient was treated with antihistaminic drug Claritin.