Sex: M
Vaccine: FLUC3, RSV
Symptoms: Abdominal tenderness, Anion gap, Areflexia, Asthenia, Back pain
Clinical narrative: developed GBS two weeks after receiving the new Pfizer's RSV vaccine in conjunction with the influenza vaccine for the first time; This is a literature report for the following literature source(s).  A 60-year-old male patient received respiratory syncytial virus (rsv) vaccine prot.subunit pref 2v (RSV VACCINE PROT.SUBUNIT PREF 2V), as dose number unknown, single (Batch/Lot number: unknown) for immunisation; influenza vaccine inact sag 4v (FLUCELVAX QUADRIVALENT), as dose number unknown, single for immunisation. The patient's relevant medical history included: "peripheral artery disease" (unspecified if ongoing); "hyperlipidemia" (unspecified if ongoing); "hypertension" (unspecified if ongoing); "trigeminal neuralgia" (unspecified if ongoing); "exacerbation of sciatica" (unspecified if ongoing), notes: tingling legs with nausea, vomiting, constipation, metallic taste, body aches, lower back pain. The patient's concomitant medications were not reported. Vaccination history included: Covid-19 vaccine (Primary Immunization series complete;  unknown manufacturer), for Covid-19 immunisation; Pfizer's covid-19 vaccine (DOSE NUMBER UNKNOWN (BOOSTER)), for Covid-19 immunisation. The following information was reported: GUILLAIN-BARRE SYNDROME (hospitalization), 2 weeks after the suspect product(s) administration, outcome "recovering", described as "developed GBS two weeks after receiving the new Pfizer's RSV vaccine in conjunction with the influenza vaccine for the first time". Therapeutic measures were taken as a result of guillain-barre syndrome. The clinical course was reported as follows: The patient presented to the emergency department (ED) with a chief complaint of progressive tingling that developed into numbness. Two weeks prior to the presentation, he experienced new-onset tingling in both of his legs accompanied by nausea, vomiting, constipation, metallic taste, body aches, and lower back pain. At that time, he was evaluated in the ED, where he had a normal neurological exam and an unremarkable computed tomography (CT) scan of his chest, abdomen, and pelvis. He was diagnosed with exacerbation of sciatica and discharged. Five days later, the patient's tingling in the lower extremities subsequently transformed into numbness, causing stumbling and difficulty walking. The symptoms then ascended to his hands and mouth, prompting his second ED visit and subsequent admission. Approximately three weeks before these symptoms appeared, the patient received Pfizer's COVID-19 vaccine booster, followed by his first-ever administration of both the influenza vaccine inact sag 4v and Pfizer's newly approved rsv vaccine prot.subunit pref 2v five days later. He reported no adverse reactions from previous COVID-19 vaccinations. His diet had recently been limited to rice cakes due to ongoing constipation and indigestion. He experienced one episode of non-bloody diarrhea after taking BISACODYL for constipation and noted a weak urinary stream without saddle anesthesia for the past three days. He did not report consumption of poultry or meat for several weeks, no home canning activities and his wife exhibited no similar symptoms despite consuming the same foods as the patient. In the ED, the patient presented with an elevated blood pressure of 148/93 mmH; vital signs were otherwise within normal limits. The electrocardiogram demonstrated normal sinus rhythm. The neurological assessment showed a normal cranial nerve exam, absent deep tendon reflexes in the bilateral Achilles, patellar, bicep, and triceps tendons, with decreased sensation across all extremities. The motor exam showed bilateral lower extremities with 0/5 strength while bilateral upper extremities were 1/5 strength. Physical examination showed mild tenderness in the lower abdominal quadrant upon deep palpation, otherwise unremarkable. Laboratory tests showed abnormalities of a white blood cell (WBC) count of 11x103/uL, sodium of 135 mEq/L, blood urea nitrogen of 21 mg/L, creatinine of 1.06 mg/dL, and magnesium of 2.6 mg/dL. Cerebrospinal fluid (CSF) examination revealed clear fluid and albuminocytologic dissociation, with an elevated protein of 84 mg/dL and normal leukocyte count of WBC 2 cells/uL. Viral panel tests for Influenza A and B, RSV, and COVID-19 were negative. A CT scan of the brain without contrast showed no abnormalities. The patient's clinical presentation and CSF findings with elevated protein levels were consistent with a diagnosis of Guillain-Barre syndrome (GBS). The patient was started on immunoglobulin (IVIg) therapy for a total of five days. Respiratory vitals were monitored closely, and fortunately, his negative inspiratory force (NIF) remained within normal limits for the duration of his hospitalization, ranging from -60 to -85 cm H20 and never dropping below -30 cm H20, so intubation and ventilatory support were not required during his stay. The patient was discharged upon completion of IVIg therapy with slight improvements in his symptoms and was instructed to follow up with outpatient neurology in two weeks. During this subsequent visit, he reported a continued lack of sensation in his hands and feet, but notably, his patellar reflex had returned for the first time since the onset of GBS. As a result, he was scheduled for an additional round of IVIg therapy at 400 mg/kg for five doses. The patient developed GBS two weeks after simultaneously receiving Pfizer's new RSV vaccine and the influenza vaccine for the first time. GBS significantly impacted the patient's ability to ambulate.; Sender's Comments: A possibly contributory role of respiratory syncytial virus vaccine in triggering the onset of Guillain-Barre syndrome cannot be fully excluded, considering the temporal relationship.  Co-intake of influenza vaccine may also be the confounding factor.  Given the patient were experiencing gastrointestinal symptoms including nausea, vomit and diarrhea around the event onset, extensive infectious panels are needed for exploring alternative etiologies.  The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators, as appropriate.