REVACCINATION WITH DIFFERENT COVID-19 VACCINE; CONFIRMED CLINICAL VACCINATION FAILURE; CONFIRMED COVID-19 INFECTION; BRAIN FOG WORSENED; This spontaneous report received from a patient via other manufacturer (Pfizer) concerned a patient of unspecified age, sex, race and ethnic origin. The patient's height, and weight were not reported. The patient's concurrent conditions included: asthma, chronic migraine, endometriosis, bipolar disorder 1, anxiety, allergies to cats, dogs and horses, drug allergy (Allergic to verapamil), and ADHD (attention deficit hyperactivity disorder). The patient received covid-19 vaccine ad26.cov2.s (Dose number in series 1) (suspension for injection, route of admin not reported, batch number: 1808609 expiry: UNKNOWN) dose was not reported, 1 total, administered on 23-MAR-2021 for covid-19 prophylaxis. Concomitant medications included amyitriptyline HCL 25 mg, Adderall XR 10 mg extended release, lamotrigine 200 mg, budesonide 0.5 mg/2 ml (used in nose via sinus rinse), Trelegy Ellipta inhaler, azelastine hydrocholride 0.1 percent, norethindrone 5 mg and Emgality for drug used for unknown indication. The patient also received non-company suspect booster of pfizer (tozinameran) (Dose number in series 2) (form of admin and route of admin was not reported, batch number:  FH8020, expiry: unknown) dose was not reported, administered on 31-OCT-2021 for covid-19 prophylaxis. It was unknown whether the patient experienced any adverse events following vaccination with pfizer (tozinameran) (Dose number in series 2). The patient additionally received non-company suspect booster of pfizer (tozinameran) (Dose number in series 3) (form of admin and route of admin was not reported, batch number: GJ2524, expiry: unknown) dose was not reported, administered on 16-SEP-2022 for covid-19 prophylaxis which was revaccination with different covid-19 vaccine. On an unspecified date in SEP-2022, the patient tested positive for covid-19 and experienced confirmed covid-19 infection (Dose number in series 3) which led to confirmed clinical vaccination failure (Dose number in series 1). The patient received non company suspect drug (drug unspecified) (form of admin, route of admin was not reported, batch number: unknown, expiry: unknown) dose was not reported, administered from 26-SEP-2022 to 30-SEP-2022 for the treatment of covid-19. On day 4 of taking covid-19 treatment medication (29-SEP-2022), the patient initially began to feel better which continued until 2 days after. However, it worsened again 3 days after and the patient developed fever. The patient's symptoms of shortness of breath, cough, nasal congestions, exhaustion and brain fog worsened (Dose number in series 3). On an unspecified date in OCT-2022 (12 days after initially testing positive for covid), the patient continued to test covid-19 positive and was symptomatic. The action taken with covid-19 vaccine ad26.cov2.s, and tozinameran was not applicable and with non-company suspect drug (unspecified) was drug discontinued. The patient had not recovered from confirmed covid-19 infection, and brain fog worsened, and the outcome of confirmed clinical vaccination failure and revaccination with different covid-19 vaccine was not reported. This report was serious (Other Medically Important Condition). This case was associated with product quality complaint: 90000255872.; Sender's Comments: V0-20221033923-covid-19 vaccine ad26.cov2.s -Confirmed clinical vaccination failure. 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. Therefore, this event(s) is considered not related.