BLURRED VISION; POTENTIAL BRUISE; CONCERNED ABOUT A BLOOD CLOT; BODY PAIN IN DIFFERENT AREAS; RIGHT UPPER LEG MORE SENSITIVE; POTENTIAL REDNESS ON SKIN OF LEG; LOT OF PAIN BEHIND RIGHT LEG MOSTLY FROM THE KNEE UP BUT LITTLE BELOW THE KNEE ALMOST TO THE TOP OF THE LEG (MOSTLY IN THE MIDDLE OF THE UPPER LEG); CHILLS, SHIVERING; HEADACHE; MUSCLE AND BODY ACHES; SWEATY; LOW GRADE FEVER; VARICOSE VEINS AT BACK OF LEG TURNED MORE BLUE AND MIGHT BE LITTLE RED; HOT ON AND OFF; This spontaneous report received from a patient concerned a 46 year old  female. The patient's height, and weight were not reported. The patient's concurrent conditions included: non alcohol user, and non smoker. The patient had no known allergies. The patient did not have any history of drug abuse or illicit drug use. The patient had no medical history to share and was generally in good health. The patient was not pregnant at the time of report.  The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 206A21A, expiry: UNKNOWN) dose was not reported, 1 total, administered on left arm on 20-AUG-2021 15:50 for prophylactic vaccination. No concomitant medications were reported.  On 21-AUG-2021, twelve hours after vaccination, like clockwork, the patient woke up at 3 AM shivering and had various body pain in different areas. By morning time, when she got up she felt that area (right upper leg) was more sensitive and then on the morning of 22-AUG-2021, it was much worse instead of getting better. On 21-AUG-2021, the patient had a headache, muscle and body aches, lot of pain behind right leg, mostly from the knee up but starting a little below the knee almost to the top of the leg, mostly in the middle of the upper leg and potential redness on skin of leg. The pain was like a bruise, it felt like she was touching a bruise when she was not (potential bruise). She was unable to confirm the appearance of the back of leg when questioned if there was a visible bruise. She was also unable to confirm if there was any swelling or heat present in the affected area. When she tried to see the back of leg she had varicose veins which had turned more blue and it might turned a little red back there. She was concerned about a blood clot as she read about that being a potential with the Janssen COVID-19 vaccine. She had chills and got sweaty. In AUG-2021, the patient felt like she had a low grade fever in general but she did not have a thermometer to measure. The patient was hot on and off. Her usual or expected side effects such as shivering, fever, various pains in other areas and headache went away. On 22-AUG-2021, her vision was blurred, she couldn't drive without glasses and usually she did not bother putting them on. The patient visited emergency room and physician's office. She did not know if this was related to the vaccine.  The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from sweaty, body pain in different areas, chills, shivering, low grade fever, and headache on AUG-2021, had not recovered from lot of pain behind right leg mostly from the knee up but little below the knee almost to the top of the leg (mostly in the middle of the upper leg), muscle and body aches, right upper leg more sensitive, and concerned about a blood clot, and the outcome of blurred vision, potential bruise, hot on and off, potential redness on skin of leg and varicose veins at back of leg turned more blue and might be little red was not reported. This report was serious (Other Medically Important Condition).; Sender's Comments: V0: Medical assessment comments not required as per the standard procedure as the case is assessed as non-serious.