Age: 16.0
Sex: F
Vaccine: MNQ, MEN
Symptoms: Lumbar puncture, Lung assist device therapy, Mechanical ventilation, Plasmapheresis, Pyrexia
Clinical narrative: HLH unknown trigger; feeling bad; head ache; slight fever/higher fever; Initial information received on 15-Jul-2025 regarding an unsolicited valid serious case received via other health care professional from Health Authorities.  This case involves a 16 years old female patient who had HLH (haemophagocytic lymphohistiocytosis) unknown trigger after receiving after receiving meningococcal A-C-Y-W135 (T CONJ) vaccine [Menquadfi].  The patient's past medical treatment(s), vaccination(s) and family history were not provided. At the time of the event, the patient had ongoing Anxiety, Depression, Attention deficit hyperactivity disorder and Drug hypersensitivity. Patient past medical history nexplanon implant.  On 19-May-2025, the patient received an unknown dose of suspect meningococcal A-C-Y-W135 (T CONJ) vaccine, solution for injection (lot number, strength and expiry date not reported) via unknown route in unknown administration site for prophylactic vaccination (Immunisation). Information on batch number and expiration date corresponding to the one at time of event occurrence.  On 21-May-2025, the patient developed HLH unknown trigger (haemophagocytic lymphohistiocytosis) with symptoms of head ache, slight fever/higher fever (pyrexia) and feeling bad (feeling abnormal) (Latency: 2 days).  Reportedly, Patient had higher fever on 23 May, multiple Doctor visits over the weekend, primary care 27 May, hospitalized & intubated 28-May and Was not taking any of her prescription medications. Autopsy multi organ damage-unknown, extensive testing being performed.   Relevant laboratory test results included: Bacterial test and Viral test - On an unknown date in May 2025: Negative Blood test, Computerised tomogram and X-ray- On an unknown date:  [unknown]  Action taken was not applicable.  The patient received corrective treatment (Intubation, ventilator, CRRT (Continuous Renal Replacement Therapy), ECMO (Extracorporeal Membrane Oxygenation) on 02-June , plasmapheresis, lumbar puncture, bone marrow and bone biopsy).   At time of reporting, the outcome was Fatal for the event HLH unknown trigger.  It is unknown if an autopsy was done.   The cause of death was reported as Haemophagocytic lymphohistiocytosis, headache, pyrexia and feeling abnormal.  Seriousness criteria: All events was assessed as medically significant and was leading to death. The patient was hospitalized 7 days after events occurred.; Sender's Comments: Sanofi company comment dated 18-Jul-2025: This case concerns a 16- year-old female patient with medical history of ongoing anxiety, depression, ADHD, drug hypersensitivity, and use of Nexplanon implant, who experienced initial symptoms of headache, fever, and general malaise, two days after receiving meningococcal A-C-Y-W135 (T CONJ) vaccine [Menquadfi]. The patient condition rapidly deteriorated with multiple doctor visits over next five days and she was hospitalized on Day 9 post -vaccination, diagnosed with haemophagocytic lymphohistiocytosis (HLH) with unknown trigger and despite aggressive interventions including CRRT, ECMO, plasmapheresis, and other treatments, the patient's outcome was fatal. Bacterial and viral tests were negative, though extensive testing was ongoing. The case was reported as medically significant with death attributed to HLH. The available information is insufficient to determine a causal relationship between MenQuadfi and HLH at this time. Given the rarity of HLH and the widespread use of meningococcal vaccines, the temporal association in isolated cases should not automatically imply causation.; Reported Cause(s) of Death: HLH unknown trigger