generalized weakness and difficulty with ambulation; fever; Systemic Inflammatory Response Syndrome; intermittently confused with situation; walked with unsteady shuffling gait; PR (Heart rate) was 110 bpm; incoherent (neurological problem); woke up several times to void at night; chills; disoriented to time, place and event; A spontaneous report was received from a physician concerning a 65 year old  male patient  (race, ethnic group unknown)  who received Moderna's COVID-19 Vaccine (mRNA-1273), and experienced systemic inflammatory response syndrome (systemic inflammatory response syndrome), generalized weakness and difficulty with ambulation (asthenia), fever (pyrexia), woke up several times to void at night (nocturia), was incoherent- neurological problem (incoherent), was disoriented to time, place and event (disorientation), walked with unsteady shuffling gait (gait disturbance), his PR (heart rate) to 110 bpm (tachycardia) and chills (chills).  The patient's current condition included metastatic small cell lung cancer, diabetes, hypertension, hyperlipidemia, fatigue, loss of appetite and shortness of breath. On 22 Jul 2019, patient had stroke. On 02-Aug-2019, patient underwent left carotid endarterectomy. Concomitant medications reported included are Jardiance (empagluflozin), losartan potassium, atorvastatin calcium, aspirin (acetylsalicylic acid), ondansetron, tramadol HCl, Tylenol (paracetamol), promethazine, robitussin DM (dextromethorphan hydrobromide, guaifenesin), xanax (alprazolam), benadryl (diphenhydramine hydrochloride), colace (docusate sodium), famotidine, prochlorperazine and dulcolax (bisacodyl).  On 12 Feb 2021, prior to onset of events, the patient received his second of two planned doses of mRNA-1273 (Batch number: unknown), for prophylaxis of COVID-19 infection.  On 12 Feb 2021, after administering the vaccine, the patient developed fever, chills and woke up several times to void at nighttime. Patient's wife stated that he was incoherent (neurological problem) on 13 Feb 2021 and was hospitalized on the same day. He was hospitalized for fever, generalized weakness and difficulty with ambulation. In emergency department he was disoriented to time, place and event, sometimes confused with situation and walked with unsteady gait. The reporter also reported that on 12 Feb 2021, patient was diagnosed with event systemic inflammatory response syndrome, grade 3.    Laboratory tests were performed, on an unknown date, the patient's heart rate was 110 bpm, blood pressure was 128/66. On 13 Feb 2021, COVID-19 test result was negative, influenza type A was negative and influenza type B was negative, urinalysis was negative for bacteria blood (peripheral) culture and no growth was seen in urine culture.  Patient was treated with fluids, ceftriaxone, tylenol and metoprolol.  On 14 Feb 2021, patient was discharged from the hospital.   The outcome of the event systemic inflammatory response syndrome was recovered and the events generalized weakness and difficulty with ambulation, fever, waking up several times to void at night, incoherent- neurological problem, disoriented to time, place and event, walking with unsteady shuffling gait, increased heart rate and chills were unknown.; 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.