Unable to think; wobbly legs; Weak legs; Unable to eat; Dizzy; Shortness of breath/ Difficulty breathing; Fever of 101 degrees Fahrenheit; Chills; Nauseated; A spontaneous report was received from a Health Care Professional concerning 69 years old female patient who received Moderna's COVID-19 vaccine (mRNA-1273) and experienced Mental impairment, which is medically significant and experienced Dyspnoea, Chills, Pyrexia, Muscular weakness, Mobility decreased, Nausea, Dizziness, Feeding disorder and Product dose omission issue of routine medicines.  The patient's medical history was provided as Covid-19 infection on OCT 2020 and current illness was provided as back problem and 11 mm gallstone.  Historical medication was reported as REMDESIVIR for Covid-19 infection.  Relevant concomitant medications were reported as Lisinopril-HCTZ daily, Mobic 15 mg daily, Tylenol 1000 mg as needed up to 3 times daily, Multivitamin, Vitamin C, Vitamin D, Vitamin B12, Calcium and Zinc.  On 05 MAR 2021, prior to the onset of the event, the patient received their first dose of two planned doses of mRNA-1273 (lot/batch: 024A21A) intramuscularly in the left arm for prophylaxis of COVID-19 infection.   On 06 MAR 2021, the patient woke and felt like she was dying, described as having difficulty breathing and almost hyperventilating. She called her daughter-in-law who was a hospital nurse who advised her to breath slowly. The patient had shortness of breath, chills, and a temperature of 101 degrees Fahrenheit. Her legs were so weak that she had to use a walker to get from her bed to the couch, where she stayed until 2:30 am Sunday morning 7Mar2021. While she was on her couch she used a heating pad and was not able to sit up because she was nauseated and dizzy. She was unable to eat anything since Friday night until Sunday afternoon at 1:30 pm. She said she couldn't think on Saturday, and she missed her medicines until she was able to resume taking them Sunday evening 07 Mar 2021. The symptoms were not treated, except for use of the heating pad on Saturday.   On 07-mar-2021, Sunday morning at 2:30 am her fever broke. The patient was not as nauseated and did not get dizzy, so she sat up. The patient legs were not as weak and were not wobbling, so she went back to her bed. She began feeling better by 6 or 7 pm on Sunday evening, with no fever, chills, and walking fine.   On 08 Mar 2021 she feels fine, excepting she has still had some shortness of breath. The patient had status post Covid-19 infection since October 2020. The patient was hospitalized and received remdesivir therapy for Covid-19 infection prior to receiving the Moderna Covid-19 first dose. She also was already scheduled for two surgeries, one on her back and one for a 11 mm gallstone removal, prior to receiving this first vaccine dose. Her doctor told her she must have the Moderna Covid-19 vaccine prior to beingable to have her surgeries. She describes her symptoms as feeling like she had Covid-19 again.    Laboratory details were not provided. Treatment information was provided as heating pad.  Action taken with mRNA-1273 in response to the events was unknown.  On 07 MAR 2021, the outcome of the event's Mental impairment, Chills, Pyrexia, Muscular weakness, Mobility decreased, Nausea, Dizziness,  feeding disorder and Product dose omission issue of routine medicine was considered as resolved.  At the of this report, the outcome of the event's Dyspnoea was considered as not resolved.; Reporter's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded. Further information has been requested.