SUSPECTED IMMUNOLOGICAL VACCINE FAILURE; DIFFICULTY SPEAKING; SLEEPY; BLURRED VISION 80 PERCENT OF THE TIME; CONFUSION; DIZZINESS; PROBLEM CONCENTRATING; JETLAGGED; CAN'T BE ON FEET FOR MORE THAN 20 MIN; TIREDNESS; FEELING SICK; This spontaneous report received from a patient concerned a 46 year white and Hispanic or Latino old female. The patient's height, and weight were not reported. The patient's concurrent conditions included hashimoto disease. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 201A21A, and expiry: UNKNOWN) dose was not reported, frequency was 1 total administered on 24-JUN-2021 to left arm for prophylactic vaccination. No concomitant medications were reported.  On 05-JUL-2021, Laboratory data included: PCR (NR: not provided) negative. On 08-JUL-2021, Laboratory data included: PCR (NR: not provided) negative. On 9 Jul 2021, the patient started to feel very tired as if she is Jetlagged. Her eye lid would close from being so tired even after 11 hours of sleeping. She is having difficulty speaking, concentrating and she is feeling dizzy and confused. On 19 Jul 2021, she felt well and better, but she still had problem concentrating and blurred vision 80 percent of the time. She can't be on her feet for more than 20 min. On 19-Jul-2021 (for 10 days), she could not go to work or take care of her kids. Her doctor was suspecting she may have Covid infection during her visit and those symptoms were post Covid syndrome. She suffered from hypothyroidism due to Hashimoto disease. She started taking anti-inflammatory medication and omega 3 as suggested by her Doctor. She was worried as she heard that she may be getting a swelling of the brain. On 13-JUL-2021, Laboratory data included: Laboratory test (NR: not provided) high levels of ATPO which are the antibodies against thyroid gland but normal TSH and T3. On 17-JUL-2021, Laboratory data included: Laboratory test (NR: not provided) high levels of ATPO which are the antibodies against the thyroid gland but normal TSH and T3. MRI (NR: not provided) neurological functions are fine, and PCR (NR: not provided) negative. On 18-JUL-2021, Laboratory data included: IgG normal (NR: not provided) negative. On 28-JUN-2021, she experienced feeling sick. On an unspecified date, the patient experienced suspected immunological vaccine failure. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from feeling sick, had not recovered from dizziness, difficulty speaking, tiredness, sleepy, blurred vision 80 percent of the time, confusion, and problem concentrating, and the outcome of jetlagged, can't be on feet for more than 20 min, and suspected immunological vaccine failure was not reported. This report was serious (Other Medically Important Condition).; Sender's Comments: V0:20210741759-COVID-19 VACCINE AD26.COV2.S-Suspected immunological vaccine failure. 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: SPECIAL SITUATIONS