ARRHYTHMIA; COMPLEX MIGRAINE; BP BOUNCING HIGH AND LOW; TROUBLE MOVING LEGS AND NO STRENGTH; TIRED; EXTREMELY WEAK; TEMPERATURE ELEVATED; ELEVATED BLOOD PRESSURE; TROUBLE WITH ARM HARDLY USE ARM; GROIN PAIN; MUSCLE ACHE; COULDN'T SLEEP; UNABLE TO WALK; This spontaneous report received from a patient concerned an 83 year old female. The patient's height, and weight were not reported. The patient's past medical history included bulbar polio diagnosed at age 15, and concurrent conditions included seasonal allergy, non-smoker, and high blood pressure. The patient received Covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported and batch number: 1802068 expiry: UNKNOWN) dose was not reported, administered on 13-MAR-2021 for prophylactic vaccination at right arm. No concomitant medications were reported. On 12-MAR-2021, Laboratory data included: SARS-CoV-2 rapid diagnostic test (NR: not provided) NEGATIVE.  On 13-MAR-2021, the patient experienced temperature elevated. On 14-MAR-2021 (Sunday) and 15-MAR-2021 (Monday), she felt bad and had elevated blood pressure (BP) and temperature. On 16-MAR-2021 (Tuesday), she felt lot better but by afternoon, she experienced loss of sight in right saw round circle with black triangle and her BP was 130/111 (77- heart rate (HR)). She developed arrhythmias. Her daughter and husband took her to the hospital. The hospital staff was concern about stroke. Her magnetic resonance imaging (MRI) and two computerized axial tomography (CAT) scans, one with iodine was performed and confirmed that she did not had stroke. Her BP was bouncing around high and low. She had trouble in moving legs were not working no strength. At one point her heavy muscle couldn't move. She reported that her BP was erratic, she was conscious but not mentally functioning, which was hard to explain. She was sent back to do scan with iodine, as health care professional was concern with blockage. Later, her MRI was performed. She started getting better and on the same day she was released from hospital after about 7 -8 hours. After coming home, she felt tired. She was diagnosed with complex migraine. On 26-MAR-2021, she started having trouble with arm and leg and she could not sleep. On 27-MAR-2021, her last muscle ache. Her BP elevated again and can hardly use her right arm. On 28-MAR-2021, her left leg was not in shape, trouble using right arm, groin area muscle is giving out with sharp pains. Treatment medications (dates unspecified) included: amlodipine, acetylsalicylic acid, and metoprolol. The action taken with Covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from arrhythmia on 16-MAR-2021, and temperature elevated, and unable to walk, had not recovered from elevated blood pressure, trouble moving legs and no strength, complex migraine, muscle ache, groin pain, and BP bouncing high and low, and the outcome of extremely weak, trouble with arm hardly use arm, tired and couldn't sleep was not reported. This report was serious (Hospitalization Caused / Prolonged, and Other Medically Important Condition).; Sender's Comments: V0: 20210353871-JANSSEN COVID-19 VACCINE Ad26.COV2.S- Arrhythmia, Complex migraine, Temperature elevated, Trouble moving legs and no strength, Tired. 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). V0: 20210353871-JANSSEN COVID-19 VACCINE Ad26.COV2.S- Elevated Blood pressure, BP bouncing high and low. This event(s) is considered not related. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There are other factors more likely to be associated with the event(s) than the drug. Specifically: MEDICAL HISTORY of High blood pressure. V0: 20210353871-JANSSEN COVID-19 VACCINE Ad26.COV2.S- Extremely Weak. This event(s) is labeled and is therefore considered potentially related.