had to limp; not being able to sleep at night; It was affecting her on the side of injection; She had right leg paralysis and severe problem ever since; Inflammation of the muscle/very painful; Both legs felt like they were on fire; unable to walk; This spontaneous case was reported by a consumer and describes the occurrence of MONOPLEGIA (She had right leg paralysis and severe problem ever since) in a 50-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Allergy. Concomitant products included LORATADINE, PSEUDOEPHEDRINE SULFATE (CLARITIN-D) for Allergy.   On 24-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 21-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 21-Apr-2021 at 6:00 PM, the patient experienced MONOPLEGIA (She had right leg paralysis and severe problem ever since) (seriousness criterion medically significant), MYOSITIS (Inflammation of the muscle/very painful), LIMB DISCOMFORT (Both legs felt like they were on fire) and GAIT INABILITY (unable to walk). On an unknown date, the patient experienced GAIT DISTURBANCE (had to limp), INSOMNIA (not being able to sleep at night) and VACCINATION SITE DISCOMFORT (It was affecting her on the side of injection). The patient was treated with Manual therapy (Massage therapy and Muscle rubs) for Myositis. At the time of the report, MONOPLEGIA (She had right leg paralysis and severe problem ever since), MYOSITIS (Inflammation of the muscle/very painful), GAIT INABILITY (unable to walk) and GAIT DISTURBANCE (had to limp) had not resolved and LIMB DISCOMFORT (Both legs felt like they were on fire), INSOMNIA (not being able to sleep at night) and VACCINATION SITE DISCOMFORT (It was affecting her on the side of injection) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood test: normal (normal) Normal.         Treatment include Muscle rubs, Massage therapy. She had right leg paralysis and severe problem ever since. It had affected her on the side of injection. The vaccine was administered on the right-sided arm. For the second dose, she had her shot in the morning and by 6pm, both legs felt like they were on fire. Her right leg muscle was stone and paralyzed and she could not move without assistance from her husband. She had consulted a doctor (second contact tab) The diagnosis was: inflammation of the muscle. Although the blood results were normal for inflammation. She had to pay for massage therapy out from her own pocket to move the muscles for seven months. It helped a little. She was still unable to walk as she had to limp and it was still very painful .She spent several months not being able to sleep at night. Doctor had advised her to take tylenol if needed or else not to take. She had applied muscle rubs. It was terrible. No hospitalization.  Concomitant medication: Claritin D once in the morning for allergy  This is a spontaneous case concerning a 50-year-old female patient with a medical history of allergy, who experienced the unexpected serious event of monoplegia. Other non serious event include myositis, limb discomfort, gait inability, gait disturbance, insomnia and vaccination site discomfort. The event monoplegia occurred on the same day after the second dose of mRNA  1273 vaccine. Monoplegia is medically significant as per IME list and at the time of report had not resolved. Patient was not hospitalized secondary to the events. Treatment included muscle rubs and massage therapy. The rechallenge is not applicable since no enough information regarding the first dose was provided. The benefit-risk relationship of mRNA  1273 vaccine  is not affected by this report.   This case was linked to MOD-2021-404099 (Patient Link).; Sender's Comments: This is a spontaneous case concerning a 50-year-old female patient with a medical history of allergy, who experienced the unexpected serious event of monoplegia. Other non serious event include myositis, limb discomfort, gait inability, gait disturbance, insomnia and vaccination site discomfort. The event monoplegia occurred on the same day after the second dose of mRNA  1273 vaccine. Monoplegia is medically significant as per IME list and at the time of report had not resolved. Patient was not hospitalized secondary to the events. Treatment included muscle rubs and massage therapy. The rechallenge is not applicable since no enough information regarding the first dose was provided. The benefit-risk relationship of mRNA  1273 vaccine  is not affected by this report.