quadriplegia; elevated protein in CSF; elevated WBC in CSF; Low grade fever; difficulty urinating; unsteadiness of gait; Retention urine; Transverse myeletis; decreased movement of lower legs; Achiness of his body; Achiness of both arms; Sensory disturbance on body; back achiness; central spinal cord lesion; Increased weakness feeling in the arms; This serious case was reported by a consumer via regulatory authority and described the occurrence of myelitis transverse in a elderly male patient who received RSVPreF3 adjuvanted (Arexvy) for prophylaxis.   The patient's past medical history included left atrial appendage closure implant (in 2021), pericardial tamponade and pericardiocentesis. Concurrent medical conditions included embolic stroke (significant for embolic stroke left MCA (Middle cerebral artery) in September of 2021), paroxysmal atrial fibrillation (PAF), obstructive sleep apnea syndrome, hypothyroidism, coronary artery disease and hyperlipidemia. Additional patient notes included No known allergies. Concomitant products included acetylsalicylic acid (Aspirin), atorvastatin, ciclosporin (Cyclosporine), levothyroxine and macrogol (Miralax).   In SEP-2023, the patient received Arexvy. In SEP-2023, less than a month after receiving Arexvy, the patient experienced myelitis transverse (Verbatim: Transverse myeletis) (serious criteria hospitalization and GSK medically significant), c1-c4 level with complete lesion of spinal cord (Verbatim: central spinal cord lesion) (serious criteria hospitalization and GSK medically significant), weakness of arms (Verbatim: Increased weakness feeling in the arms) (serious criteria hospitalization), back pain (Verbatim: back achiness) (serious criteria hospitalization), mobility decreased (Verbatim: decreased movement of lower legs) (serious criteria hospitalization), general body pain (Verbatim: Achiness of his body) (serious criteria hospitalization), pain in arm (Verbatim: Achiness of both arms) (serious criteria hospitalization) and sensory disturbance (Verbatim: Sensory disturbance on body) (serious criteria hospitalization). On 19-SEP-2023, the patient experienced urination difficulty (Verbatim: difficulty urinating) (serious criteria hospitalization), unsteady gait (Verbatim: unsteadiness of gait) (serious criteria hospitalization) and urinary retention (Verbatim: Retention urine) (serious criteria hospitalization and GSK medically significant). On 20-SEP-2023, the patient experienced low grade fever (Verbatim: Low grade fever) (serious criteria hospitalization). On 22-SEP-2023, the patient experienced cerebrospinal fluid protein increased (Verbatim: elevated protein in CSF) (serious criteria hospitalization and GSK medically significant) and csf wbc increased (Verbatim: elevated WBC in CSF) (serious criteria hospitalization and GSK medically significant). On 26-SEP-2023, the patient experienced quadriplegia (Verbatim: quadriplegia) (serious criteria hospitalization and GSK medically significant). The patient was treated with aciclovir (Acyclovir), methylprednisolone sodium succinate (Solumedrol) and operations and procedures (Plasma Exchange). The outcome of the myelitis transverse, quadriplegia, c1-c4 level with complete lesion of spinal cord, weakness of arms, cerebrospinal fluid protein increased, csf wbc increased, back pain, urination difficulty, unsteady gait, low grade fever, mobility decreased, general body pain, pain in arm, sensory disturbance and urinary retention were not reported.   It was unknown if the reporter considered the myelitis transverse, quadriplegia, c1-c4 level with complete lesion of spinal cord, weakness of arms, cerebrospinal fluid protein increased, csf wbc increased, back pain, urination difficulty, unsteady gait, low grade fever, mobility decreased, general body pain, pain in arm, sensory disturbance and urinary retention to be related to Arexvy.    It was unknown if the company considered the myelitis transverse, quadriplegia, c1-c4 level with complete lesion of spinal cord, weakness of arms, cerebrospinal fluid protein increased, csf wbc increased, back pain, urination difficulty, unsteady gait, low grade fever, mobility decreased, general body pain, pain in arm, sensory disturbance and urinary retention to be related to Arexvy.   Additional Information: GSK Receipt Date: 09-NOV-2023 The patient self-reported this case. The patient's concomitant medication included as Aspirin 81mg daily, Atorvastatin 40mg daily, Cyclosporine ophthalmic 1 drop both eyes BID, Levothyroxine 100mcg daily, Miralax as needed. The patient was completely well on 17th September 2023.  From 18th September 2023 to 19th September 2023, the patient might had some subjective achiness on his body both arms and upper back though nothing localizing. On 19th September 2023, the patient developed difficulty urinating with retention and some unsteadiness of gait in evening. On 20th September 2023, the patient developed low grade fever at home up to 99.6.  The patient also developed decreased movement of lower legs and some increased weakness feeling in the arms and some subjective sensory changes on the body as well.  This led to admission.  On 21st September 2023 to 23rd September 2023, the patient started on empiric IV Acyclovir. On 22nd September 2023, LP showed 145 wbc (white blood cells), protein of 142, glucose of 47.  The patient started on Solumedrol 1gm IV daily x 5 days.  On 26th September 2023, the patient with significant quadriplegia, plasma exchanges started every other day 5 times treatments on 29th September 2023, VDRL was negative.  MRI C spine showed central spinal cord lesion from C1 to C6 with patchy enhancement.  The slow progression of the symptoms, enhancement of the lesion and elevated protein/WBCs in the CSF was more consistent with transverse myelitis. The patient had no prior vaccinations for this reported event. The patient did not have acute illness at the time of vaccination. The follow up would not possible as no contact details were available.