Peripheral neuropathy in her feet; Multiple myeloma; Burning sensations in the bottom of her feet; cold; Balance is a little off; Numbness; Tingling; Monoclonal G; This spontaneous case was reported by a patient and describes the occurrence of NEUROPATHY PERIPHERAL (Peripheral neuropathy in her feet) and PLASMA CELL MYELOMA (Multiple myeloma) in an adult female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 061E21A and 001M21A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.  Concomitant products included INFLUENZA VACCINE (FLU VACCINE VII) and PNEUMOCOCCAL VACCINE for an unknown indication.   On 07-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 04-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 19-Aug-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 11-Apr-2022, received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced NEUROPATHY PERIPHERAL (Peripheral neuropathy in her feet) (seriousness criterion medically significant), PLASMA CELL MYELOMA (Multiple myeloma) (seriousness criterion medically significant), BURNING SENSATION (Burning sensations in the bottom of her feet), NASOPHARYNGITIS (cold), BALANCE DISORDER (Balance is a little off), HYPOAESTHESIA (Numbness), PARAESTHESIA (Tingling) and HYPERGAMMAGLOBULINAEMIA BENIGN MONOCLONAL (Monoclonal G). The patient was treated with METOPROLOL TARTRATE (BETAONE) ongoing since an unknown date at an unspecified dose and frequency and GABAPENTIN ongoing since an unknown date at an unspecified dose and frequency. At the time of the report, NEUROPATHY PERIPHERAL (Peripheral neuropathy in her feet), PLASMA CELL MYELOMA (Multiple myeloma), BURNING SENSATION (Burning sensations in the bottom of her feet), NASOPHARYNGITIS (cold), HYPOAESTHESIA (Numbness), PARAESTHESIA (Tingling) and HYPERGAMMAGLOBULINAEMIA BENIGN MONOCLONAL (Monoclonal G) had not resolved and BALANCE DISORDER (Balance is a little off) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Electromyogram: Did not definitively show peripheral neuropathy.         There was no swelling. She felt her balance was a little off because of her feet. Patient couldn't go to the gym and walk on the treadmill because of her feet. Her symptoms were not getting better or worse with medication. Patient was wearing a heart monitor, taking a beta blocker, and also taking gabapentin. She has been taking her regular flu and pneumonia vaccines. Since she has taken the COVID-19 vaccines she has not had COVID-19, though she has had a cold once. Patient had plans to see a podiatrist for her symptoms next.  Company comment:  This spontaneous case concerns an adult female patient (unknown age), with no medical history reported, who experienced the unexpected, serious (medically significant) events of neuropathy peripheral and plasma cell myeloma. The events occurred approximately within 1-2 months of her first 2 doses of the Moderna COVID-19 Vaccine (mRNA-1273). The report mentioned the patient had developed peripheral neuropathy in her feet with numbness, tingling, and burning sensations in the bottom of her feet. She felt her balance was a disturbed because of her feet. She had taken an electro-nerve conduction test which did not definitively show peripheral neuropathy. She has been discussing her symptoms with a neurologist and hematologist who discussed multiple myeloma, and Monoclonal G of Undetermined Source. She was under treatment with Gabapentin, and her symptoms were not getting better or worse. The benefit-risk relationship of Moderna COVID-19 Vaccine (mRNA-1273) is not affected by this report.   This case was linked to MOD-2023-741605 (Patient Link).