HALLUCINATION; LIGHT SENSITIVITY TO EYE; ATTENTION IMPAIRED; SEVERE HEADACHE; This spontaneous report received from a consumer concerned a patient of unspecified age, sex, race, and ethnicity. The patient's height, and weight were not reported. The patient's concurrent conditions included: sinusitis, migraines, zithromax allergy, gelatin allergy, benzo allergy, latex, eggs-hlas allergy, and alpha-gal allergy. The patient received Covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: unknown expiry: unknown) dose was not reported, 1 total administered on 03-APR-2021 for prophylactic vaccination. The batch number was not reported. The Company is unable to perform follow-up to request batch/lot numbers. Concomitant medications included acetylsalicylic acid/caffeine, paracetamol for drug used for unknown indication, chlorphenamine maleate, Ibuprofen, pseudoephedrine hydrochloride for drug used for unknown indication, ketorolac tromethamine for migraine, promethazine for migraine, and topiramate for migraine.  On 03-APR-2021, the patient had worst, severe headache. The headache was in the frontal lobe normally located. He felt like vision was a little off and described it as headache was moving too fast for brain. The patient had stated that on an unspecified date he experienced some abnormal sights almost like hallucinations, and his mental status was not changed. but he felt like light sensitivity to eye and attention impaired (feeling of eye piercing in the light) . His attention had severely affected. he could not focus on anything. On 15-Apr-2021, the patient visited to Physician office and he rated headache as 4-5 out of 10. The patient denied leg pain, shortness of breath, chest pain, or dizziness.  On 15-APR-2021, Laboratory data included: Blood pressure (NR: not provided) 114/80 mmHg, Body temperature (NR: not provided) 98 F, respirations 16 per minute, Fibrin D dimer high (NR: 0.00 - 0.49) 0.49 mg{FEU}/L, Hematocrit (NR: 34.0 - 46.6) 41.2 %, Hemoglobin (NR: 11.1 - 15.9) 13.9 g/dL, Oxygen saturation decreased (NR: not provided) Oxygen saturation 98% on Room air, Platelet count (NR: 150 - 450) 174 10*3/uL, Radial pulse (NR: not provided) 73 /min, Red blood cell count abnormal (NR: 3.77 - 5.28) 4.18 10*3/uL, and White blood cells (NR: 3.4 - 10.8) 6.3 10*3/uL. patient physical exam was negative. The plan was to determine with Magnetic resonance imaging (MRI) of brain and Magnetic resonance (MR) venography of the patient to rule out any blood clot. It was advised to patient to visit to an Emergency Room. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient was recovering from headache, and the outcome of light sensitivity to eye, attention impaired and hallucination was not reported. This report was serious (Other Medically Important Condition).; Sender's Comments: V0:20211111627-JANSSEN COVID-19 VACCINE Ad26.COV2.S- hallucination- This event(s) is considered unassessable. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s).