Burning on the right lower leg; felt like a clot on the left leg a huge purplish - maroon color bruise; hard knot, felt like 3 number 2 pencils combined together in a horizontal fashion; Felt weak; Stinging on the right lower leg below the knee; knee hurt so bad; This case was received via an unknown source (no reference has been entered for a health authority or license partner) on 01-Jun-2021 and was forwarded to Moderna on 01-Jun-2021.    This spontaneous case was reported by a consumer and describes the occurrence of BURNING SENSATION (Burning on the right lower leg), CONTUSION (felt like a clot on the left leg a huge purplish - maroon color bruise), MASS (hard knot, felt like 3 number 2 pencils combined together in a horizontal fashion), ASTHENIA (Felt weak) and PAIN (Stinging on the right lower leg below the knee) in a 72-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 037B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Hypertension and Hypercholesterolaemia. Concomitant products included EVOLOCUMAB (REPATHA) for Hypercholesterolaemia, CARVEDILOL, OLMESARTAN and VERAPAMIL for an unknown indication.    On 01-May-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 06-May-2021, the patient experienced BURNING SENSATION (Burning on the right lower leg), CONTUSION (felt like a clot on the left leg a huge purplish - maroon color bruise), MASS (hard knot, felt like 3 number 2 pencils combined together in a horizontal fashion), ASTHENIA (Felt weak), PAIN (Stinging on the right lower leg below the knee) and ARTHRALGIA (knee hurt so bad). The patient was treated with PARACETAMOL (TYLENOL) at a dose of 1 dosage form and TOCOPHEROL (VITAMIN E [TOCOPHEROL]) for Contusion, at a dose of 1 dosage form. On 25-May-2021, CONTUSION (felt like a clot on the left leg a huge purplish - maroon color bruise) had resolved. At the time of the report, BURNING SENSATION (Burning on the right lower leg) and MASS (hard knot, felt like 3 number 2 pencils combined together in a horizontal fashion) had not resolved and ASTHENIA (Felt weak), PAIN (Stinging on the right lower leg below the knee) and ARTHRALGIA (knee hurt so bad) outcome was unknown.        The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.       Consumer calls in to report receiving the first dose of the Moderna Covid-19 vaccine in the left arm on 1May2021 and experienced burning and stinging on the right lower leg below the knee within 5 days to a week of getting the vaccine.  Consumer describes, "felt like a clot; on the left leg a huge purplish - maroon color bruise that felt like a hard knot....felt like 3 number 2 pencils combined together in a horizontal fashion."  Consumer is supposed to the take second dose on 27Jun2021, but states unsure if will take it.  Consumer also felt weak.  Tingling and burning are ongoing, and the knee hurt so bad that the consumer thought about going to the ER but did not due to fear of exposure to Covid-19. Consumer reports seeing their primary care doctor about their symptoms but that the doctor did not know what the hardness was.  There is a milder severity on the side of left leg.    Bruising on left leg phased away last week but the knot is still present.