SMALL STROKE; PAIN IN RIGHT LEG/BLOOD CLOT IN RIGHT LEG/DVT; ARTHRITIS PAIN IN JOINTS; FEVER; This spontaneous report received from a patient concerned a 50 year old female. The patient's height, and weight were not reported. The patient's concurrent condition included low blood pressure. The patient received Covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 041A21A, expiry: 05-AUG-2021) dose was not reported, 1 total, administered on 07-APR-2021 for prophylactic vaccination. No concomitant medications were reported. On 07-APR-2021, on first night, the patient developed fever of 100 F. On 08-APR-2021, by morning fever was gone. On the same day, she developed arthritis pain in her joints, it stayed for few days then it went away. In MAY-2021, she experienced pain in right leg, the pain elevated, and she wasn't sure what it was. On 08-MAY-2021, she had small stroke, blood clot in right leg and deep vein thrombosis (DVT) and she was taken to the emergency room (ER) and admitted to the hospital for 1 night. She received treatment with blood thinner Eliquis (apixaban) for DVT. She has blood pressure (BP), her ER doctor was concerned about her BP and her doctor advised her to monitor her BP. She also informed that she uses wheelchair all the time. Also, if her leg remained down for more than 20 minutes it turns, and she tried to elevate it most of the time.  The action taken with Covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from arthritis pain in joints on APR-2021, and fever on 08-APR-2021, and had not recovered from pain in right leg/blood clot in right leg/DVT, and small stroke. This report was serious (Hospitalization Caused / Prolonged).; Sender's Comments: V0: This spontaneous report received from a patient concerned a 50 year old White (not Hispanic or Latino) female who experienced right leg pain and small stroke and was noted to have deep vein thrombosis 31 days after receiving the Janssen Covid-19 vaccine. The patient's height and weight were not reported, but patient claims that she was a little overweight. Patient claimed to be in good shape and used to have 'low blood pressure'. Patient has no family history of clotting disorders but she claimed to have history of bleeding/clotting problems even before receiving the vaccine. Information regarding allergy, smoking history, illicit drug use and alcohol abuse were not provided. No concomitant medications reported and patient did not take oral contraceptive pills (OCP's). Patient had a fever the night day the patient received the vaccine. Fever was gone the following day but patient experienced arthritic pain in her joints (unspecified) but resolved after a few days. Later, patient developed pain on right leg that was progressing. Thirty-one (31) days post vaccine, patient sought consult at the emergency room (ER). She was noted to have blood clot in the right leg and was diagnosed with deep vein thrombosis (DVT) on the right leg. She was also diagnosed with stroke. She was admitted to the hospital for 1 night and treatment with apixaban (Eliquis) was started. As of this report, patient still used wheelchair. She still kept her leg elevated most of the time since it turned purple if left dangling for 20 minutes. The information available precludes a complete and meaningful assessment. The occurrence of DVT and stroke could represent background incidence of such events in the general population. Hence, a relationship with Janssen Covid-19 vaccine cannot be ruled out and thus the relationship is considered indeterminate. Additional information has been requested.