Nerve going to legs was damaged by the vaccine/Couldn't walk; Patient would sleep 20-23 hours a day; Patient stated that he hasn't been able to work; Patient had long haul covid symptoms; COVID-19; Myelin sheath damage/The next day or 2 left leg went numb; This spontaneous case was reported by a patient and describes the occurrence of DEMYELINATION (Myelin sheath damage/The next day or 2 left leg went numb) in a 61-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Wheelchair user (The patient reported that he's been in a "wheelchair for 2 months, 6 months), Walker user (The patient reported that he's been in a "wheelchair for 2 months, 6 months using a walker), Walking aid user (has been using a walking cane until about 6 weeks ago), Back surgery in 2014 and Back surgery in 2017.   In October 2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In November 2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In April 2021, the patient experienced DEMYELINATION (Myelin sheath damage/The next day or 2 left leg went numb) (seriousness criterion medically significant). In October 2021, the patient experienced COVID-19 (COVID-19). In March 2022, the patient experienced POST-ACUTE COVID-19 SYNDROME (Patient had long haul covid symptoms). On an unknown date, the patient experienced NERVE INJURY (Nerve going to legs was damaged by the vaccine/Couldn't walk), HYPERSOMNIA (Patient would sleep 20-23 hours a day) and IMPAIRED WORK ABILITY (Patient stated that he hasn't been able to work). In September 2022, POST-ACUTE COVID-19 SYNDROME (Patient had long haul covid symptoms) had resolved. At the time of the report, DEMYELINATION (Myelin sheath damage/The next day or 2 left leg went numb) and NERVE INJURY (Nerve going to legs was damaged by the vaccine/Couldn't walk) had not resolved and HYPERSOMNIA (Patient would sleep 20-23 hours a day), IMPAIRED WORK ABILITY (Patient stated that he hasn't been able to work) and COVID-19 (COVID-19) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In October 2021, SARS-CoV-2 test: Positive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered DEMYELINATION (Myelin sheath damage/The next day or 2 left leg went numb) and NERVE INJURY (Nerve going to legs was damaged by the vaccine/Couldn't walk) to be related. No further causality assessments were provided for HYPERSOMNIA (Patient would sleep 20-23 hours a day), IMPAIRED WORK ABILITY (Patient stated that he hasn't been able to work), COVID-19 (COVID-19) and POST-ACUTE COVID-19 SYNDROME (Patient had long haul covid symptoms).    No concomitant medications were provided. After the second shot, the next day or 2 patient's left leg went numb and they thought it had to do with back surgery. But in April, neurologist said that the Myelin Sheath, the nerve going to legs was damaged by the vaccine.Patient also mentioned regarding his COVID diagnosis, patient was not hospitalized but mentioned had long haul COVID symptoms, severe fatigue, sick, very sick, from March -September.  Came home from therapy and go to bed.   Company Comment This spontaneous case concerns a 61-years-old-male patient, with  medical history of Back surgery in 2014 and  2017 who experienced the unexpected seriousness criterion medically significant event of demyelination, the unexpected events of hypersomnia (AESI), Covid-19, nerve injury, impaired work ability and Post-acute COVID-19 syndrome unknown days after 2nd.  dose of  mRNA- 1273 vaccine. In October 2021, SARS-CoV-2 test was Positive. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Events seriousness was assessed based on medical judgement.